diff --git a/racket/src/ChezScheme/csug/system.stex b/racket/src/ChezScheme/csug/system.stex
index dd3852e87f..32af7f3ab3 100644
--- a/racket/src/ChezScheme/csug/system.stex
+++ b/racket/src/ChezScheme/csug/system.stex
@@ -1898,7 +1898,9 @@ an expression.
 or unannotated value.
 \scheme{expand/optimize} expands the expression in environment \var{env}
 and passes the expression through the source optimizer \scheme{cp0}
-(unless \scheme{cp0} is disabled via \scheme{run-cp0}).
+and a type-inferring optimizer \scheme{cptypes}
+(unless \scheme{cp0} and \scheme{cptypes} are disabled via \scheme{run-cp0},
+or unless \scheme{cptypes} is disabled via \scheme{enable-type-recovery}).
 It also simplifies \scheme{letrec} and \scheme{letrec*} expressions within
 the expression and makes their undefined checks explicit.
 It returns an object representing the expanded, simplified, and optimized form.
@@ -1906,7 +1908,7 @@ If no environment is provided, it defaults to the environment
 returned by \scheme{interaction-environment}.
 
 \scheme{expand/optimize} is primarily useful for understanding what
-\scheme{cp0} does and does not optimize.
+\scheme{cp0} plus \scheme{cptypes} does and does not optimize.
 Many optimizations are performed later in the compiler,
 so \scheme{expand/optimize} does not give a complete picture of
 optimizations performed.
@@ -2864,9 +2866,10 @@ When the parameter is set to \scheme{#f}, the message is not printed.
 \endentryheader
 
 \noindent
-These parameters control the operation of \scheme{cp0}, a source
-optimization pass that runs after macro expansion and prior
+These parameters control the operation of \scheme{cp0} plus \scheme{cptypes}, source
+optimization passes that run after macro expansion and prior
 to most other compiler passes.
+
 \scheme{cp0} performs procedure inlining, in which the code of one
 procedure is inlined at points where it is called by other procedures,
 as well as copy propagation, constant folding, useless code
@@ -2874,6 +2877,13 @@ elimination, and several related optimizations.
 The algorithm used by the optimizer is described in detail in the paper
 ``Fast and effective procedure inlining''~\cite{waddell:sas97}.
 
+\scheme{cptypes} performs additional optimizations based on type
+information about primitives, such as the fact that \scheme{+} always
+returns a number; since it primarily removes unneecssary run-time
+checks, \scheme{cptypes} primarly benefits compilation in safe mode.
+The \scheme{cptypes} pass can be independently disabled through the
+\scheme{enable-type-recovery} parameter.
+
 When \scheme{cp0} is enabled, the programmer can count on the compiler
 to fold constants, eliminate unnecessary \scheme{let} bindings, and
 eliminate unnecessary and inaccessible code.
@@ -2903,9 +2913,9 @@ if \scheme{e} turns out to be an unassigned variable, and count on
 the entire \scheme{case} expression to be folded if \scheme{e} turns
 out to be a constant.
 
-It is possible to see what \scheme{cp0} does with an expression
+It is possible to see what \scheme{cp0} plus \scheme{cptypes} does with an expression
 via the procedure \index{\scheme{expand/optimize}}\scheme{expand/optimize},
-which expands its argument and passes the result through \scheme{cp0}, as
+which expands its argument and passes the result through \scheme{cp0} and \scheme{cptypes}, as
 illustrated by the following transcript.
 
 \schemedisplay
@@ -2914,9 +2924,9 @@ illustrated by the following transcript.
     '(lambda (x)
        (case x [(a) 1] [(b c) 2] [(d) 3] [else 4])))
 (lambda (x)
-  (if (#2%memv x '(a))
+  (if (#2%member x '(a))
       1
-      (if (#2%memv x '(b c)) 2 (if (#2%memv x '(d)) 3 4))))
+      (if (#2%member x '(b c)) 2 (if (#2%member x '(d)) 3 4))))
 > (expand/optimize
     '(+ (let ([f (lambda (x)
                 (case x [(a) 1] [(b c) 2] [(d) 3] [else 4]))])
@@ -2928,7 +2938,7 @@ illustrated by the following transcript.
 In the first example, the \scheme{let} expression produced by \scheme{case}
 is eliminated, and in the second, the entire expression is optimized down
 to the constant \scheme{17}.
-Although not shown by \scheme{expand/optimize}, the \scheme{memv} calls
+Although not shown by \scheme{expand/optimize}, the \scheme{member} calls
 in the output code for the first example will be replaced by calls to the
 less expensive \scheme{eq?} by a later pass of the compiler.
 Additional examples are given in the description
@@ -2937,9 +2947,9 @@ of \scheme{expand/optimize}.
 The value of \scheme{run-cp0} must be a procedure.
 Whenever the compiler is invoked on a Scheme form, the value \var{p}
 of this parameter is called to determine whether and how
-\scheme{cp0} is run.
-\var{p} receives two arguments: \var{cp0}, the entry point into
-\scheme{cp0}, and \var{x}, the form being compiled.
+\scheme{cp0} and \scheme{cptypes} are run.
+\var{p} receives two arguments: \var{cp0}, the entry point into the
+\scheme{cp0} plus \scheme{cptypes} passes, and \var{x}, the form being compiled.
 The default value of \scheme{run-cp0} simply invokes \var{cp0} on
 \var{x}, then \var{cp0} again on the result.
 The second run is useful in some cases because the first run