diff --git a/collects/scribble/html-render.ss b/collects/scribble/html-render.ss
index 35e94ce9aa..f454eeb8ab 100644
--- a/collects/scribble/html-render.ss
+++ b/collects/scribble/html-render.ss
@@ -272,12 +272,16 @@
                         (current-subdirectory))
             (super get-dest-directory)))
 
-      (define/private (derive-filename d)
-        (format "~a.html" (regexp-replace*
-                           "[^-a-zA-Z0-9_=]"
-                           (or (format "~a" (part-tag d))
-                               (content->string (part-title-content d)))
-                           "_")))
+      (define/private (derive-filename d ht)
+        (let ([fn (format "~a.html" (regexp-replace*
+                                     "[^-a-zA-Z0-9_=]"
+                                     (or (format "~a" (part-tag d))
+                                         (content->string (part-title-content d)
+                                                          this d ht))
+                                     "_"))])
+          (when ((string-length fn) . >= . 100)
+            (error "file name too long (need a tag):" fn))
+          fn))
 
       (define/override (collect ds fns)
         (super collect ds (map (lambda (fn)
@@ -297,7 +301,7 @@
                                              1
                                              (add1 prev-sub))])
             (if (= 1 prev-sub)
-                (let ([filename (derive-filename d)])
+                (let ([filename (derive-filename d ht)])
                   (parameterize ([current-output-file (build-path (path-only (current-output-file))
                                                                   filename)])
                     (super collect-part d parent ht number)))
@@ -417,7 +421,7 @@
                                      (make-element
                                       (if parent
                                           (make-target-url (if prev
-                                                               (derive-filename prev)
+                                                               (derive-filename prev ht)
                                                                "index.html"))
                                           "nonavigation")
                                       prev-content)
@@ -426,14 +430,14 @@
                                       (if parent
                                           (make-target-url 
                                            (if (toc-part? parent)
-                                               (derive-filename parent)
+                                               (derive-filename parent ht)
                                                "index.html"))
                                           "nonavigation")
                                       up-content)
                                      sep-element
                                      (make-element
                                       (if next
-                                          (make-target-url (derive-filename next))
+                                          (make-target-url (derive-filename next ht))
                                           "nonavigation")
                                       next-content))))))))
                               d
@@ -447,7 +451,7 @@
                      (next-separate-page)))
             ;; Render as just a link, and put the actual 
             ;; content in a new file:
-            (let* ([filename (derive-filename d)]
+            (let* ([filename (derive-filename d ht)]
                    [full-path (build-path (path-only (current-output-file))
                                           filename)])
               (parameterize ([on-separate-page #t])
diff --git a/collects/scribblings/guide/define-struct.scrbl b/collects/scribblings/guide/define-struct.scrbl
index 435c1fba6b..8aa67bd484 100644
--- a/collects/scribblings/guide/define-struct.scrbl
+++ b/collects/scribblings/guide/define-struct.scrbl
@@ -39,13 +39,13 @@ are built from @scheme[_struct-id] and the @scheme[_field-id]s:
 @itemize{
 
  @item{@schemeidfont{make-}@scheme[_struct-id] : a
-       @defterm{constructor} function that takes as many arguments as
+       @deftech{constructor} function that takes as many arguments as
        the number of @scheme[_field-id]s, and returns an instance of
        the structure type.
 
        @examples[(make-posn 1 2)]}
 
- @item{@scheme[_struct-id]@schemeidfont{?} : a @defterm{predicate}
+ @item{@scheme[_struct-id]@schemeidfont{?} : a @deftech{predicate}
        function that takes a single argument and returns @scheme[#t]
        if it is an instance of the structure type, @scheme[#f]
        otherwise.
@@ -53,14 +53,14 @@ are built from @scheme[_struct-id] and the @scheme[_field-id]s:
        @examples[(posn? 3) (posn? (make-posn 1 2))]}
 
  @item{@scheme[_struct-id]@schemeidfont{-}@scheme[_field-id] : for
-       each @scheme[_field-id], an @defterm{accessor} that extracts
+       each @scheme[_field-id], an @deftech{accessor} that extracts
        the value of the corresponding field from an instance of the
        structure type.
 
        @examples[(posn-x (make-posn 1 2)) (posn-y (make-posn 1 2))]}
 
  @item{@schemeidfont{set-}@scheme[_struct-id]@schemeidfont{-}@scheme[_field-id]@schemeidfont{!} : for
-       each @scheme[_field-id], a @defterm{mutator} that sets
+       each @scheme[_field-id], a @deftech{mutator} that sets
        the value of the corresponding field in an instance of the
        structure type.
 
@@ -68,6 +68,12 @@ are built from @scheme[_struct-id] and the @scheme[_field-id]s:
                  (posn-x p)
                  (set-posn-x! p 10)
                  (posn-x p)]}
+
+ @item{@schemeidfont{struct:}@scheme[_struct-id] : a
+       @deftech{structure type descriptor}, which is a value that
+       represents the structure type (as opposed to a single instance)
+       for certain reflective operations.}
+
 }
 
 A @scheme[define-struct] form places no constraints on the kinds of
@@ -76,7 +82,7 @@ type. For example, @scheme[(make-posn "apple" #f)] produces an
 instance of @scheme[posn], even though @scheme["apple"] and
 @scheme[#f] are not valid coordinates for the obvious uses of
 @scheme[posn] instances. Enforcing constraints on field values, such
-as requiring them to be numbers, is the job of a contract, as
+as requiring them to be numbers, is normally the job of a contract, as
 discussed later in @secref["guide:contracts"].
 
 @; ------------------------------------------------------------
@@ -114,7 +120,7 @@ p
 ]
 
 @; ------------------------------------------------------------
-@section{Opaque versus Transparent Stucture Types}
+@section[#:tag "guide:trans-struct"]{Opaque versus Transparent Stucture Types}
 
 With a structure type definition like
 
@@ -141,11 +147,176 @@ field-name sequence:
 An instance of a transparent structure type prints like a vector, and
 it shows the content of the structure's fields. A transparent
 structure type also allows reflective operations, like
-@scheme[struct?] and @scheme[struct-info], to be used on its
-instances (see @secref["reflection"]).
+@scheme[struct?] and @scheme[struct-info], to be used on its instances
+(see @secref["reflection"]). Different values for @scheme[#:inspector]
+support more controlled access to reflective operations.
 
 Structure types are opaque by default, because opaque structure
 instances provide more encapsulation guarantees. That is, a library
 can use an opaque structure to encapsulate data, and clients of the
 library cannot manipulate the data in the structure except as allowed
 by the library.
+
+@; ------------------------------------------------------------
+@section{More Structure Type Options}
+
+The full syntax of @scheme[define-struct] supports many options, both
+at the structure-type level and at the level of individual fields:
+
+@specform/subs[(define-struct id-maybe-super (field ...) 
+                              struct-option ...)
+               ([id-maybe-super struct-id
+                                (struct-id super-id)]
+                [field field-id
+                       [field-id field-option ...]])]
+
+A @scheme[_struct-option] always starts with a keyword:
+
+ @specspecsubform[#:immutable]{
+
+   Causes all fields of the structure type to be immutable, and
+   supresses the definition of @tech{mutator} procedures.
+
+   @defexamples[(define-struct fixed-posn (x y) #:immutable)
+                (set-fixed-posn-x! (make-fixed-posn 1 2) 0)]
+
+   Th @scheme[#:immutable] option can also be used as a
+   @scheme[_field-option], in which case it makes an individual field
+   immutable.
+
+   @defexamples[
+   (define-struct person ([name #:immutable] age))
+   (define friend (make-person "Barney" 5))
+   (set-person-age! friend 6)
+   (set-person-name! friend "Mary")]}
+
+ @specspecsubform[(code:line #:inspector inspector-expr)]{
+  Controls reflective access to structure instances, as discussed
+  in the previous section (@secref["guide:trans-struct"]).
+ }
+
+ @specspecsubform[(code:line #:auto-value auto-expr)]{
+
+  Specifies a value to be used for all automatic fields in the
+  structure type, where an automatic field is indicated by the
+  @scheme[#:auto] @scheme[_field-option]. The structure type's
+  constructor omits arguments for automatic fields.
+
+  @defexamples[
+    (define-struct posn (x y [z #:auto])
+                   #:inspector #f
+                   #:auto-value 0)
+    (make-posn 1 2)
+  ]}
+
+ @specspecsubform[(code:line #:guard guard-expr)]{
+  Specifies a guard procedure to be called whenever an instance of
+  the structure type is created. The guard takes as many arguments
+  as non-automatic fields in the structure type, and it should return
+  the same number of values. The guard can raise an exception if one
+  of the given arguments is unacceptable, or it can convert an
+  argument.
+
+ @defexamples[
+   (define-struct thing (name)
+                  #:inspector #f
+                  #:guard (lambda (name type-name)
+                            (cond
+                              [(string? name) name]
+                              [(number? name) 
+                               (number->string name)]
+                              [else (error "bad name" name)])))
+   (make-thing "apple")
+   (make-thing 1/2)
+   (make-thing #f)]
+
+  Unlike the constructor for a procedure type, the guard is called even when
+  subtype instances are created. In that case, only the fields accepted by
+  the constructor are provided to the guard (but the subtype's guard gets
+  both the original fields and fields added by the subtype).
+
+ @defexamples[
+  (define-struct (person thing) (age)
+                 #:inspector #f
+                 #:guard (lambda (name age type-name)
+                           (if (negative? age)
+                               (error "bad age" age)
+                               (values name age))))
+  (make-person "John" 10)
+  (make-person "Mary" -1)
+  (make-person #f 10)]}
+
+ @specspecsubform[(code:line #:property prop-expr val-exr)]{
+   Associates a property and value with the structure type.  For
+   example, the @scheme[prop:procedure] property allows a structure
+   instance to be used as a function; the property value determines
+   how a call is implemented when using the structure as a function.
+
+ @defexamples[
+   (define-struct greeter (name)
+                  #:property prop:procedure 
+                             (lambda (self other)
+                               (string-append
+                                "Hi " other
+                                ", I'm " (greeter-name self))))
+   (define joe-greet (make-greeter "Joe"))
+   (greeter-name joe-greet)
+   (joe-greet "Mary")
+   (joe-greet "John")]}
+                               
+ @specspecsubform[(code:line #:super super-expr)]{
+
+  An alternative to supplying a @scheme[super-id] next to
+  @scheme[struct-id]. Instead of the name of a structure type (which is
+  not an expression), @scheme[super-expr] should produce a
+  @tech{structure type descriptor} value. An advantage of
+  @scheme[#:super] is that structure type descriptors are values, so
+  they can be passed to procedures.
+
+  @defexamples[
+    (define (make-raven-constructor super-type)
+      (define-struct raven ()
+                     #:super super-type
+                     #:inspector #f
+                     #:property prop:procedure (lambda (self)
+                                                 'nevermore))
+      make-raven)
+    (let ([r ((make-raven-constructor struct:posn) 1 2)])
+      (list r (r)))
+    (let ([r ((make-raven-constructor struct:thing) "apple")])
+      (list r (r)))]}
+
+
+@; ------------------------------------------------------------
+@section{Structure Type Generativity}
+
+Each time that a @scheme[define-struct] form is evaluated, it
+generates a structure type that is distinct from all existing
+structure types, even if some other structure type has the same name
+and fields.
+
+This generativity is useful for enforcing abstractions and
+implementing programs such as interpreters, but beware of placing a
+@scheme[define-struct] form in positions that are evaluated multiple
+times.
+
+@defexamples[
+(define (add-bigger-fish lst)
+  (define-struct fish (size) #:inspector #f)
+  (cond
+   [(null? lst) (list (make-fish 1))]
+   [else (cons (make-fish (* 2 (fish-size (car lst))))
+               lst)]))
+
+(add-bigger-fish null)
+(add-bigger-fish (add-bigger-fish null))
+]
+@defs+int[
+[(define-struct fish (size) #:inspector #f)
+ (define (add-bigger-fish lst)
+   (cond
+    [(null? lst) (list (make-fish 1))]
+    [else (cons (make-fish (* 2 (fish-size (car lst))))
+                lst)]))]
+(add-bigger-fish (add-bigger-fish null))
+]
diff --git a/collects/scribblings/reference/reference.scrbl b/collects/scribblings/reference/reference.scrbl
index 30ccc6ba1b..e6f11aa7f5 100644
--- a/collects/scribblings/reference/reference.scrbl
+++ b/collects/scribblings/reference/reference.scrbl
@@ -17,6 +17,7 @@ language.
 @include-section["syntax.scrbl"]
 @include-section["derived.scrbl"]
 @include-section["data.scrbl"]
+@include-section["struct.scrbl"]
 
 @;------------------------------------------------------------------------
 
diff --git a/collects/scribblings/reference/struct.scrbl b/collects/scribblings/reference/struct.scrbl
new file mode 100644
index 0000000000..6b77c1274d
--- /dev/null
+++ b/collects/scribblings/reference/struct.scrbl
@@ -0,0 +1,196 @@
+#reader(lib "docreader.ss" "scribble")
+@require["mz.ss"]
+
+@title[#:tag "mz:structures"]{Structures}
+
+A @pidefterm{structure type} is a record datatype composing a number
+of @idefterm{fields}. A @pidefterm{structure}, an instance of a
+structure type, is a first-class value that contains a value for each
+field of the structure type. A structure instance is created with a
+type-specific @tech{constructor} procedure, and its field values are
+accessed and changed with type-specific @tech{accessor} and
+@tech{mutator} procedures. In addition, each structure type has a
+@tech{predicate} procedure that answers @scheme[#t] for instances of
+the structure type and @scheme[#f] for any other value.
+
+A structure type's fields are essentially unnamed, though names are
+supported for error-reporting purposes. The constructor procedure
+takes one value for each field of the structure type, except that some
+of the fields of a structure type can be @deftech{automatic fields};
+the @tech{automatic fields} are initialized to a constant that is
+associated with the structure type, and the corresponding arguments
+are omitted for the constructor procedure. All automatic fields in a
+structure type follow the non-automatic fields.
+
+A structure type can be created as a @pidefterm{structure subtype} of
+an existing base structure type. An instance of a structure subtype
+can always be used as an instance of the base structure type, but the
+subtype gets its own predicate procedure, and it may have its own
+fields in addition to the fields of the base type.
+
+A structure subtype ``inherits'' the fields of its base type. If the
+base type has @math{m} fields, and if @math{n} fields are specified
+for the new structure subtype, then the resulting structure type has
+@math{m+n} fields. The value for automatic fields can be different in
+a subtype than in its base type.
+
+If @math{m'} of the original @math{m} fields are non-automatic (where
+@math{m'<m}), and @math{n'} of the new fields are automatic (where
+@math{n'<n}), then @math{m'+n'} field values must be provided to the
+subtype's constructor procedure. Values for the first @math{m} fields
+of a subtype instance are accessed with selector procedures for the
+original base type (or its supertypes), and the last @math{n} are
+accessed with subtype-specific selectors. Subtype-specific
+@tech{accessors} and @tech{mutators} for the first @math{m} fields do
+not exist.
+
+@section{Creating Structure Types}
+
+@defproc[(make-struct-type [name symbol?]
+                           [super-type (or/c struct-type? false/c)]
+                           [init-field-k non-negative-exact-integer?]
+                           [auto-field-k non-negative-exact-integer?]
+                           [auto-v any/c #f]
+                           [props (listof (cons/c struct-type-property?
+                                                  any/c))
+                                  null]
+                           [inspector (or/c inspector? false/c)
+                                      (current-inspector)]
+                           [proc-spec (or/c procedure? 
+                                            non-negative-exact-integer?
+                                            false/c)
+                                      #f]
+                           [immutables (listof non-negative-exact-integer?)
+                                       null]
+                           [guard (or/c procedure? false/c) #f])
+          struct-type?]{
+
+Creates a new structure type.  The @scheme[name] argument is used as
+the type name. If @scheme[super-type] is not @scheme[#f], the new type
+is a subtype of the corresponding structure type.
+
+The new structure type has @scheme[(+ init-field-k auto-field-k)]
+fields (in addition to any fields from @scheme[super-type]), but only
+@scheme[init-field-k] constructor arguments (in addition to any
+constructor arguments from @scheme[super-type]). The remaining
+fields are initialized with @scheme[auto-v].
+ 
+The @scheme{props} argument is a list of pairs, where the @scheme[car]
+of each pair is a structure type property descriptor, and the
+@scheme[cdr] is an arbitrary value. See @secref["mz:structprops"] for
+more information about properties.
+
+The @scheme[inspector] argument controls access to reflective
+information about the structure type and its instances; see
+@secref["mz:inspectors"] for more information.
+
+If @scheme[proc-spec] is an integer or procedure, instances of the
+structure type act as procedures. See @secref["mz:procstructs"] for
+further information.  Providing a non-@scheme[#f] value for
+@scheme[proc-spec] is the same as pairing the value with
+@scheme[prop:procedure] in @scheme[props], plus including
+@scheme[proc-spec] in @scheme[immutables] when
+@scheme[proc-spec] is an integer.
+
+The @scheme[immutables] argument provides a list of field
+positions. Each element in the list must be unique, otherwise
+@exnraise[exn:fail:contract]. Each element must also fall in the range
+@scheme[0] (inclusive) to @scheme[init-field-k] (exclusive), otherwise
+@exnraise[exn:fail:contract].
+
+The @scheme[guard-proc] argument is either a procedure of @math{n}
+arguments or @scheme[#f], where @math{n} is the number of arguments
+for the new structure type's constructor (i.e., @scheme[init-field-k]
+plus constructor arguments implied by @scheme[super-type], if any). If
+@scheme[guard-proc] is a procedure, then the procedure is called
+whenever an instance of the type is constructed, or whenever an
+instance of a subtype is created.  The arguments to
+@scheme[guard-proc] are the values provided for the structure's first
+@math{n} fields, followed by the name of the instantiated structure
+type (which is @scheme[name], unless a subtype is instantiated). The
+@scheme[guard-proc] result must be @math{n} values, which become the
+actual values for the structure's fields. The @scheme[guard-proc] can
+raise an exception to prevent creation of a structure with the given
+field values. If a structure subtype has its own guard, the subtype
+guard is applied first, and the first @math{n} values produced by the
+subtype's guard procedure become the first @math{n} arguments to
+@scheme[guard-proc].
+
+The result of @scheme[make-struct-type] is five values:
+%
+@itemize{
+
+ @item{a @tech{structure type descriptor},}
+
+ @item{a @tech{constructor} procedure,}
+
+ @item{a @tech{predicate} procedure,}
+
+ @item{an @tech{accessor} procedure, which consumes a structure and a field
+ index between @math{0} (inclusive) and
+ @math{@scheme[init-field-k]+@scheme[auto-field-k]} (exclusive),
+ and}
+
+ @item{a @tech{mutator} procedure, which consumes a structure, a field
+ index, and a field value.}
+
+}
+
+@examples[
+(define-values (struct:a make-a a? a-ref a-set!) 
+  (make-struct-type 'a #f 2 1 'uninitialized)) 
+(define an-a (make-a 'x 'y)) 
+(a-ref an-a 1)
+(a-ref an-a 2)
+(define a-first (make-struct-field-accessor a-ref 0)) 
+(a-first an-a)
+
+(define-values (struct:b make-b b? b-ref b-set!) 
+  (make-struct-type 'b struct:a 1 2 'b-uninitialized))
+(define a-b (make-b 'x 'y 'z)) 
+(a-ref a-b 1)
+(a-ref a-b 2)
+(b-ref a-b 0)
+(b-ref a-b 1)
+(b-ref a-b 2)
+
+(define-values (struct:c make-c c? c-ref c-set!) 
+  (make-struct-type 'c struct:b 0 0 #f null (make-inspector) #f null
+                    (code:comment #,(t "guard checks for a number, and makes it inexact"))
+                    (lambda (a1 a2 b1 name)
+                      (unless (number? a2)
+                        (error (string->symbol (format "make-~a" name))
+                               "second field must be a number"))
+                      (values a1 (exact->inexact a2) b1))))
+(make-c 'x 'y 'z)
+(define a-c (make-c 'x 2 'z))
+(a-ref a-c 1)
+]}
+
+@defproc[(make-struct-field-accessor [accessor-proc procedure?]
+                                     [field-pos-k exact-nonnegative-integer?]
+                                     [field-name symbol?])
+         procedure?]{
+
+Returns a field accessor that is equivalent to @scheme[(lambda (s)
+(accessor-proc s field-pos-k))].  The @scheme[accessor-proc] must be
+an @tech{accessor} returned by @scheme[make-struct-type]. The name of the
+resulting procedure for debugging purposes is derived from
+@scheme[field-name] and the name of @scheme[accessor-proc]'s
+structure type.
+
+For examples, see @scheme[make-struct-type].}
+
+@defproc[(make-struct-field-mutator [mutator-proc procedure?]
+                                    [field-pos-k exact-nonnegative-integer?]
+                                    [field-name symbol?])
+         procedure?]{
+
+Returns a field mutator that is equivalent to @scheme[(lambda (s v)
+(mutator-proc s field-pos-k v))].  The @scheme[mutator-proc] must be
+a @tech{mutator} returned by @scheme[make-struct-type]. The name of the
+resulting procedure for debugging purposes is derived from
+@scheme[field-name] and the name of @scheme[mutator-proc]'s
+structure type.
+
+For examples, see @scheme[make-struct-type].}
diff --git a/collects/scribblings/reference/syntax.scrbl b/collects/scribblings/reference/syntax.scrbl
index d9160b502a..55f61c113e 100644
--- a/collects/scribblings/reference/syntax.scrbl
+++ b/collects/scribblings/reference/syntax.scrbl
@@ -354,7 +354,7 @@ Like @scheme[lambda], but without support for keyword or optional arguments.
 }
 
 @;------------------------------------------------------------------------
-@section{Local Binding: @scheme[let], @scheme[let*], and @scheme[letrec]}
+@section[#:tag "mz:let"]{Local Binding: @scheme[let], @scheme[let*], and @scheme[letrec]}
 
 @defform*[[(let ([id val-expr] ...) body ...+)
            (let proc-id ([id init-expr] ...) body ...+)]]{