diff --git a/collects/compiler/cm-accomplice.ss b/collects/compiler/cm-accomplice.ss
new file mode 100644
index 0000000000..9cf2b293a9
--- /dev/null
+++ b/collects/compiler/cm-accomplice.ss
@@ -0,0 +1,5 @@
+#lang scheme/base
+
+(require mzlib/cm-accomplice)
+
+(provide (all-from-out mzlib/cm-accomplice))
diff --git a/collects/compiler/cm.ss b/collects/compiler/cm.ss
new file mode 100644
index 0000000000..fb85ff0bf9
--- /dev/null
+++ b/collects/compiler/cm.ss
@@ -0,0 +1,5 @@
+#lang scheme/base
+
+(require mzlib/cm)
+
+(provide (all-from-out mzlib/cm))
diff --git a/collects/scheme/mpair.ss b/collects/scheme/mpair.ss
index 01c0d41b4b..2051d7c4cb 100644
--- a/collects/scheme/mpair.ss
+++ b/collects/scheme/mpair.ss
@@ -8,6 +8,7 @@
          mappend
          mappend!
          mreverse
+         mreverse!
          mlist-tail
          mlist-ref
          mmemq
@@ -103,10 +104,11 @@
   (case-lambda
     [() null]
     [(a) a]
-    [(a b) (let loop ([atail a])
-             (cond [(null? atail) b]
-                   [(null? (mcdr atail)) (set-mcdr! atail b) a]
-                   [else (loop (mcdr atail))]))]
+    [(a b) (if (null? a)
+               b
+               (let loop ([atail a])
+                 (cond [(null? (mcdr atail)) (set-mcdr! atail b) a]
+                       [else (loop (mcdr atail))])))]
     [(a . l) (mappend! a (apply mappend! l))]))
 
 (define (mreverse l)
@@ -115,6 +117,14 @@
      [(null? l) a]
      [else (loop (mcdr l) (mcons (mcar l) a))])))
 
+(define (mreverse! l)
+  (let loop ([l l][prev null])
+    (cond
+     [(null? l) prev]
+     [else (let ([next (mcdr l)])
+             (set-mcdr! l prev)
+             (loop next l))])))
+
 (define (mlist-tail l n)
   (cond
    [(zero? n) l]
diff --git a/collects/scribblings/mzc/cc.scrbl b/collects/scribblings/mzc/cc.scrbl
new file mode 100644
index 0000000000..8cf176d3c4
--- /dev/null
+++ b/collects/scribblings/mzc/cc.scrbl
@@ -0,0 +1,5 @@
+#lang scribble/doc
+@(require scribble/manual
+          "common.ss")
+
+@title[#:tag "cc"]{Compiling and Linking C Extensions}
diff --git a/collects/scribblings/mzc/common.ss b/collects/scribblings/mzc/common.ss
new file mode 100644
index 0000000000..3b1bcd0a02
--- /dev/null
+++ b/collects/scribblings/mzc/common.ss
@@ -0,0 +1,7 @@
+#lang scheme/base
+(require scribble/manual)
+
+(provide mzc)
+
+(define mzc (exec "mzc"))
+
diff --git a/collects/scribblings/mzc/exe.scrbl b/collects/scribblings/mzc/exe.scrbl
new file mode 100644
index 0000000000..2d5c16bde6
--- /dev/null
+++ b/collects/scribblings/mzc/exe.scrbl
@@ -0,0 +1,5 @@
+#lang scribble/doc
+@(require scribble/manual
+          "common.ss")
+
+@title[#:tag "exe"]{Creating and Packaging Stand-Alone Executables}
diff --git a/collects/scribblings/mzc/ext.scrbl b/collects/scribblings/mzc/ext.scrbl
new file mode 100644
index 0000000000..70f053648e
--- /dev/null
+++ b/collects/scribblings/mzc/ext.scrbl
@@ -0,0 +1,5 @@
+#lang scribble/doc
+@(require scribble/manual
+          "common.ss")
+
+@title[#:tag "ext"]{Compiling to Native Code via C}
diff --git a/collects/scribblings/mzc/info.ss b/collects/scribblings/mzc/info.ss
new file mode 100644
index 0000000000..53aeb9b6fc
--- /dev/null
+++ b/collects/scribblings/mzc/info.ss
@@ -0,0 +1,4 @@
+(module info setup/infotab
+  (define name "Scribblings: mzc")
+  (define scribblings '(("mzc.scrbl" (multi-page))))
+  (define doc-categories '(tool)))
diff --git a/collects/scribblings/mzc/make.scrbl b/collects/scribblings/mzc/make.scrbl
new file mode 100644
index 0000000000..5022883895
--- /dev/null
+++ b/collects/scribblings/mzc/make.scrbl
@@ -0,0 +1,251 @@
+#lang scribble/doc
+@(require scribble/manual
+          scribble/bnf
+          "common.ss"
+          (for-label scheme/base
+                     scheme/include
+                     scheme/contract
+                     compiler/cm
+                     compiler/cm-accomplice))
+
+@title[#:tag "make"]{Compiling Modified Modules to Bytecode}
+
+The default mode for @|mzc| is to accept filenames for Scheme modules
+to be compiled to bytecode format. Modules are re-compiled only if the
+source Scheme file is newer than the bytecode file, or if any imported
+module is recompiled.
+
+@; ----------------------------------------------------------------------
+
+@section{Bytecode Files}
+
+A file @filepath{@nonterm{name}.@nonterm{ext}} is compiled to bytecode
+that is saved as @filepath{compiled/@nonterm{name}_@nonterm{ext}.zo}
+relative to the file. As a result, the bytecode file is normally used
+automatically when @filepath{@nonterm{name}.@nonterm{ext}} is required
+as a module, since the underlying @scheme[load/use-compiled] operation
+detects such a bytecode file.
+
+For example, in a directory that contains the following files:
+
+@itemize{
+
+ @item{@filepath{a.scm}:
+
+@schememod[
+scheme
+(require "b.scm" "c.scm")
+(+ b c)
+]}
+
+ @item{@filepath{b.scm}:
+
+@schememod[
+scheme
+(provide b)
+(define b 1)
+]}
+
+ @item{@filepath{c.scm}:
+
+@schememod[
+scheme
+(provide c)
+(define c 1)
+]}}
+
+then
+
+@commandline{mzc a.scm}
+
+triggers the creation of @filepath{compiled/a_ss.zo},
+@filepath{compiled/b_ss.zo}, and @filepath{compiled/c_ss.zo}.
+A subsequent
+
+@commandline{mzscheme a.scm}
+
+loads bytecode from the generated @filepath{.zo} files, paying attention
+to the @filepath{.scm} sources only to confirm that each
+@filepath{.zo} file has a later timestamp.
+
+In contrast,
+
+@commandline{mzc b.scm c.scm}
+
+would create only @filepath{compiled/b_scm.zo} and
+@filepath{compiled/c_scm.zo}, since neither @filepath{b.scm} nor
+@filepath{c.scm} imports @filepath{a.scm}.
+
+@; ----------------------------------------------------------------------
+
+@section{Dependency Files}
+
+In addition to a bytecode file, @|mzc| creates a file
+@filepath{compiled/@nonterm{name}_@nonterm{ext}.dep} that records
+dependencies of the compiled module on other module files.  Using this
+dependency information, a re-compilation request via @|mzc| can
+consult both the source file's timestamp and the timestamps for the
+sources and bytecode of imported modules.  Furthermore, imported
+modules are themselves compiled as necessary, including updating the
+bytecode and dependency files for the imported modules, transitively.
+
+Continuing the @exec{mzc a.scm} example from the previous section, the
+@|mzc| creates @filepath{compiled/a_scm.dep},
+@filepath{compiled/b_scm.dep}, and @filepath{compiled/c_scm.dep} at
+the same time as the @filepath{.zo} files. The
+@filepath{compiled/a_scm.dep} file records the dependency of
+@filepath{a.scm} on @filepath{b.scm}, @filepath{c.scm} and the
+@schememodname[scheme] library. If the @filepath{b.scm} file is
+modified (so that its timestamp changes), then running
+
+@commandline{mzc a.scm}
+
+again rebuilds @filepath{compiled/a_ss.zo} and
+@filepath{compiled/b_ss.zo}.
+
+For module files that are within library collections, @exec{setup-plt}
+uses the same @filepath{.zo} and @filepath{.dep} conventions and files
+as @|mzc|, so the two tools can be used together.
+
+@; ----------------------------------------------------------------------
+
+@section{Scheme Compilation Manager API}
+
+@defmodule[compiler/cm]{The @schememodname[compiler/cm] module
+implements the compilation and dependency management used by @|mzc|
+and @exec{setup-plt}.}
+
+@defproc[(make-compilation-manager-load/use-compiled-handler)
+         (path? (or/c symbol? false/c) . -> . any)]{
+
+Returns a procedure suitable as a value for the
+@scheme[current-load/use-compiled] parameter. The returned procedure
+passes it arguments on to the @scheme[current-load/use-compiled]
+procedure that is installed when
+@scheme[make-compilation-manager-load/use-compiled-handler] is called,
+but first it automatically compiles a source file to a @filepath{.zo}
+file if
+
+@itemize{
+
+ @item{the file is expected to contain a module (i.e., the second
+ argument to the handler is a symbol);}
+
+ @item{the value of each of @scheme[current-eval],
+ @scheme[current-load], and @scheme[current-namespace] is the same as
+ when @scheme[make-compilation-manager-load/use-compiled-handler] was
+ called;}
+
+ @item{the value of @scheme[use-compiled-file-paths] contains the
+ first path that was present when
+ @scheme[make-compilation-manager-load/use-compiled-handler] was
+ called;}
+
+ @item{the value of @scheme[current-load/use-compiled] is the result
+ of this procedure; and}
+
+ @item{one of the following holds:
+
+ @itemize{
+
+  @item{the source file is newer than the @filepath{.zo} file in the
+        first sub-directory listed in @scheme[use-compiled-file-paths]
+        (at the time that
+        @scheme[make-compilation-manager-load/use-compiled-handler]
+        was called)}
+
+  @item{no @filepath{.dep} file exists next to the @filepath{.zo}
+        file;}
+
+  @item{the version recorded in the @filepath{.dep} file does not
+        match the result of @scheme[(version)];}
+
+  @item{one of the files listed in the @filepath{.dep} file has a
+        @filepath{.zo} timestamp newer than the one recorded in the
+        @filepath{.dep} file.}
+
+  }}
+
+}
+
+After the handler procedure compiles a @filepath{.zo} file, it creates
+a corresponding @filepath{.dep} file that lists the current version,
+plus the @filepath{.zo} timestamp for every file that is
+@scheme[require]d by the module in the compiled file. Additional
+dependencies can be installed during compilation via
+@schememodname[compiler/cm-accomplice].
+
+The handler caches timestamps when it checks @filepath{.dep} files,
+and the cache is maintained across calls to the same handler. The
+cache is not consulted to compare the immediate source file to its
+@filepath{.zo} file, which means that the caching behavior is
+consistent with the caching of the default module name resolver (see
+@scheme[current-module-name-resolver]).
+
+If @scheme[use-compiled-file-paths] contains an empty list when
+@scheme[make-compilation-manager-load/use-compiled-handler] is called,
+then @scheme[exn:fail:contract] exception is raised.
+
+@emph{Do not} install the result of
+@scheme[make-compilation-manager-load/use-compiled-handler] when the
+current namespace contains already-loaded versions of modules that may
+need to be recompiled---unless the already-loaded modules are never
+referenced by not-yet-loaded modules. References to already-loaded
+modules may produce compiled files with inconsistent timestamps and/or
+@filepath{.dep} files with incorrect information.}
+
+
+@defproc[(managed-compile-zo [file path-string?]) void?]{
+
+Compiles the given module source file to a @filepath{.zo}, installing
+a compilation-manager handler while the file is compiled (so that
+required modules are also compiled), and creating a @filepath{.dep} file
+to record the timestamps of immediate files used to compile the source
+(i.e., files @scheme[require]d in the source).}
+
+
+@defboolparam[trust-existing-zos trust?]{
+
+A parameter that is intended for use by @exec{setup-plt} when
+installing with pre-built @filepath{.zo} files. It causes a
+compilation-manager @scheme[load/use-compiled] handler to ``touch''
+out-of-date @filepath{.zo} files instead of re-compiling from source.}
+
+
+@defproc[(make-caching-managed-compile-zo)
+         (path-string? . -> . void?)]{
+
+Returns a procedure that behaves like @scheme[managed-compile-zo], but
+a cache of timestamp information is preserved across calls to the
+procedure.}
+
+
+@defparam[manager-compile-notify-handler notify (path? . -> . any)]{
+
+A parameter for a procedure of one argument that is called whenever a
+compilation starts. The argument to the procedure is the file's path.}
+
+
+@defparam[manager-compile-trace-handler notify (string? . -> . any)]{
+
+A parameter for a procedure of one argument that is called to report
+ compilation-manager actions, such as checking a file. The argument to
+ the procedure is a string.}
+
+@; ----------------------------------------------------------------------
+
+@section{Compilation Manager Hook for Syntax Transformers}
+
+@defmodule[compiler/cm-accomplice]
+
+@defproc[(register-external-file [file (and path? complete-path?)]) void?]{
+
+Registers the complete path @scheme[file] with a compilation manager
+implemented by @schememodname[compiler/cm], if one is active. The
+compilation manager then records (in a @filepath{.dep} file) the path
+as contributing to the implementation of the module currently being
+compiled. Afterward, if the registered file is modified, the
+compilation manager will know to recompile the module.
+
+The @scheme[include] macro, for example, calls this procedure with the
+path of an included file as it expands an @scheme[include] form.}
diff --git a/collects/scribblings/mzc/mzc.scrbl b/collects/scribblings/mzc/mzc.scrbl
new file mode 100644
index 0000000000..3880a40f93
--- /dev/null
+++ b/collects/scribblings/mzc/mzc.scrbl
@@ -0,0 +1,53 @@
+#lang scribble/doc
+@(require scribble/manual
+          "common.ss")
+
+@(define rare @emph{This mode is rarely useful.})
+
+@title{@exec{mzc}: Compilation and Packaging}
+
+The @exec{mzc} tool is a kind of Swiss-army knife for PLT Scheme
+compilation and packaging tasks. Its main action is determined through
+one of the following command-line flags:
+
+@itemize{
+
+ @item{@as-index{@DFlag{make}} or @as-index{@Flag{k}} (the default) :
+       Compiles Scheme modules and all transitive imports to
+       bytecode. See @secref["make"].}
+
+ @item{@as-index{@DFlag{cc}}, @as-index{@DFlag{ld}},
+       @as-index{@DFlag{xform}} or @as-index{@Flag{x}} : Compiles,
+       links or transforms (for GC cooperation) C code to extend the
+       PLT Scheme runtime system. See @secref["cc"]. Using the
+       @scheme[scheme/foreign] FFI is often better; see
+       @other-manual['(lib "scribblings/foreign/foreign.scrbl")].}
+
+ @item{@as-index{@DFlag{exe}}, @as-index{@DFlag{gui-exe}}, or
+       @as-index{@DFlag{exe-dir}} : Creates an executable to run a
+       Scheme module, or assembles all support libraries to move an
+       executable to a new filesystem. See @secref["exe"].}
+
+ @item{@as-index{@DFlag{collection-plt}} or @as-index{@DFlag{plt}} :
+       packages Scheme code for installation into a different PLT
+       Scheme installation. See @secref["plt"]. @|PLaneT| is usually a
+       better alternative.}
+
+ @item{@as-index{@DFlag{extension}}, @as-index{@Flag{e}},
+       @as-index{@DFlag{c-source}}, or @as-index{@Flag{c}} : Compiles
+       Scheme code to a native-code extension via C. See
+       @secref["ext"]. @|rare|}
+
+ @item{@as-index{@DFlag{zo}}, @as-index{@Flag{z}}, or
+       @as-index{@DFlag{collection-zo}} : Compiles Scheme code to
+       bytecode, without following transitive imports. See
+       @secref["zo"]. @|rare|}
+
+}
+
+@include-section["make.scrbl"]
+@include-section["cc.scrbl"]
+@include-section["exe.scrbl"]
+@include-section["plt.scrbl"]
+@include-section["ext.scrbl"]
+@include-section["zo.scrbl"]
diff --git a/collects/scribblings/mzc/plt.scrbl b/collects/scribblings/mzc/plt.scrbl
new file mode 100644
index 0000000000..4ed848c836
--- /dev/null
+++ b/collects/scribblings/mzc/plt.scrbl
@@ -0,0 +1,5 @@
+#lang scribble/doc
+@(require scribble/manual
+          "common.ss")
+
+@title[#:tag "plt"]{Packaging Library Collections}
diff --git a/collects/scribblings/mzc/zo.scrbl b/collects/scribblings/mzc/zo.scrbl
new file mode 100644
index 0000000000..f82baf0a95
--- /dev/null
+++ b/collects/scribblings/mzc/zo.scrbl
@@ -0,0 +1,8 @@
+#lang scribble/doc
+@(require scribble/manual
+          "common.ss")
+
+@title[#:tag "zo"]{Compiling to Bytecode}
+
+The @DFlag{zo}/@Flag{z} mode for @|mzc| is an improverished form of
+the default @DFlag{make}/@Flag{k} mode described in @secref["make"].
diff --git a/collects/scribblings/reference/mpairs.scrbl b/collects/scribblings/reference/mpairs.scrbl
index 952f231c7f..0676fa0f71 100644
--- a/collects/scribblings/reference/mpairs.scrbl
+++ b/collects/scribblings/reference/mpairs.scrbl
@@ -95,14 +95,16 @@ Like @scheme[list-tail], but for @tech{mutable lists}.}
 
 Like @scheme[append], but for @tech{mutable lists}.}
 
+
 @defproc*[([(mappend! [mlst mlist?] ...) mlist?]
            [(mappend! [mlst mlist?] ... [v any/c]) any/c])]{
 
-The @scheme[mappend!] procedure appends the given lists by mutating the tail of
-each to refer to the next, using @scheme[set-mcdr!]. Empty lists are silently
-ignored; in particular, the result of calling @scheme[mappend!] with one or
-more empty lists is the same as the result of the call with the empty lists
-removed from the set of arguments.}
+The @scheme[mappend!] procedure appends the given lists by mutating
+the tail of each to refer to the next, using @scheme[set-mcdr!]. Empty
+lists are dropped; in particular, the result of calling
+@scheme[mappend!] with one or more empty lists is the same as the
+result of the call with the empty lists removed from the set of
+arguments.}
 
 
 @defproc[(mreverse [mlst mlist?]) mlist?]{
@@ -110,6 +112,13 @@ removed from the set of arguments.}
 Like @scheme[reverse], but for @tech{mutable lists}.}
 
 
+@defproc[(mreverse! [mlst mlist?]) mlist?]{
+
+Like @scheme[mreverse], but destructively reverses the list by using
+all of the mutable pairs in @scheme[mlst] and changing them with
+@scheme[set-mcdr!].}
+
+
 @defproc[(mmap [proc procedure?] [mlst mlist?] ...+) 
          mlist?]{
 
diff --git a/collects/scribblings/start/manuals.ss b/collects/scribblings/start/manuals.ss
index d1c8862bfe..710c710724 100644
--- a/collects/scribblings/start/manuals.ss
+++ b/collects/scribblings/start/manuals.ss
@@ -79,7 +79,7 @@
                                                         the-cat]
                                                        [else 
                                                         (fprintf (current-error-port)
-                                                                 "WARNING: base category: ~e from: ~e"
+                                                                 "WARNING: bad base category: ~e from: ~e\n"
                                                                  cat
                                                                  dir)]))
                                                    ;; Priority
diff --git a/collects/tests/mzscheme/mpair.ss b/collects/tests/mzscheme/mpair.ss
new file mode 100644
index 0000000000..81b044e468
--- /dev/null
+++ b/collects/tests/mzscheme/mpair.ss
@@ -0,0 +1,55 @@
+
+(load-relative "loadtest.ss")
+
+(Section 'mpair)
+
+(require scheme/mpair)
+
+
+;; ----------------------------------------
+;; mreverse!
+
+(test null mreverse! null)
+(test (mlist 1) mreverse! (mlist 1))
+(test (mlist 3 2 1) mreverse! (mlist 1 2 3))
+
+(define a (mlist 1 2 3))
+(test (mlist 3 2 1) mreverse! a)
+(test (mlist 1) values a)
+
+;; ----------------------------------------
+;; mappend!
+
+;; no args
+(test null mappend!)
+
+;; one arg
+(test (mlist 3 4 5) mappend! (mlist 3 4 5))
+
+;; two args
+(test (mlist 3 4 5 6) mappend! (mlist 3 4) (mlist 5 6))
+
+(define a (mlist 3 4))
+(test (mlist 3 4 5 6) mappend! a (mlist 5 6))
+(test (mlist 3 4 5 6) values a)
+
+(test (mlist 3 4 5) mappend! null (mlist 3 4 5))
+
+;; three args
+(test (mlist 3 4 5 6 7 8)
+        mappend! (mlist 3 4) (mlist 5 6) (mlist 7 8))
+(test (mlist 3 4 5 6) mappend! (mlist 3 4) null (mlist 5 6))
+
+(define a2 (mlist 3 4))
+(test (mlist 3 4 5 6) mappend! null a2 null (mlist 5 6))
+(test (mlist 3 4 5 6) values a2)
+
+(define a3result (mcons 3 'bogus))
+(set-mcdr! a3result a3result)
+(define a3 (mlist 3))
+(test a3result mappend! a3 a3)
+(test a3result values a3)
+
+;; ----------------------------------------
+
+(report-errs)
diff --git a/collects/tests/mzscheme/mzlib.ss b/collects/tests/mzscheme/mzlib.ss
index 8706819290..c970d920ca 100644
--- a/collects/tests/mzscheme/mzlib.ss
+++ b/collects/tests/mzscheme/mzlib.ss
@@ -4,6 +4,8 @@
 
 (load-relative "loadtest.ss")
 
+(load-in-sandbox "mpair.ss")
+
 (load-in-sandbox "md5.ss")
 
 (load-in-sandbox "etc.ss")