diff --git a/collects/gui-debugger/debug-tool.rkt b/collects/gui-debugger/debug-tool.rkt
index 9bef7cbbb5..b0e2fb1dcb 100644
--- a/collects/gui-debugger/debug-tool.rkt
+++ b/collects/gui-debugger/debug-tool.rkt
@@ -1,14 +1,14 @@
-#lang racket
+#lang racket/base
 
 ;; DrRacket's debugging tool
 
-(require mzlib/etc
-         mzlib/list
-         mzlib/class
-         mzlib/unit
-         mzlib/contract
-         mred
-         mzlib/match
+(require racket/function
+         racket/list
+         racket/class
+         racket/unit
+         racket/contract
+         racket/match
+         racket/gui
          drscheme/tool
          "marks.rkt"
          mrlib/switchable-button
@@ -20,7 +20,8 @@
          string-constants
          lang/debugger-language-interface
          images/compile-time
-         (for-syntax racket/class
+         (for-syntax racket/base
+                     racket/class
                      racket/draw
                      images/icons/arrow
                      images/icons/control
@@ -112,7 +113,7 @@
     ;; (<form>)                   => (<form>)
     ;; (<form> <arg1> ... <argn>) => (<form> ...)
     (define trim-expr-str
-      (opt-lambda (str [len 10])
+      (lambda (str [len 10])
         (let* ([strlen (string-length str)]
                [starts-with-paren (and (> strlen 0)
                                        (char=? (string-ref str 0) #\())]
@@ -157,7 +158,7 @@
         [else v]))
     
     (define filename->defs
-      (opt-lambda (source [default #f])
+      (lambda (source [default #f])
         (let/ec k
           (cond
             [(is-a? source editor<%>) source]
@@ -985,7 +986,7 @@
                           (rest frames))))))
 
         (define/public suspend-gui
-          (opt-lambda (frames status [switch-tabs? #f] [already-stopped? #f])
+          (lambda (frames status [switch-tabs? #f] [already-stopped? #f])
             (let ([top-of-stack? (zero? (get-frame-num))]
                   [status-message (send (get-frame) get-status-message)])
               (set! want-suspend-on-break? #f)
@@ -1052,7 +1053,7 @@
         
         (define/public suspend
           ;; ==called from user thread==
-          (opt-lambda (break-handler frames [status #f])
+          (lambda (break-handler frames [status #f])
             ;; suspend-sema ensures that we allow only one suspended thread
             ;;  at a time
             (cond
diff --git a/collects/honu/core/private/syntax.rkt b/collects/honu/core/private/syntax.rkt
index ee17c9c9e8..a296f73464 100644
--- a/collects/honu/core/private/syntax.rkt
+++ b/collects/honu/core/private/syntax.rkt
@@ -1,8 +1,9 @@
-#lang racket
+#lang racket/base
 
 (provide (all-defined-out))
 
-(require (for-syntax syntax/define
+(require (for-syntax racket/base
+                     syntax/define
                      "transformer.rkt"))
 
 #|
diff --git a/collects/lazy/lazy-tool.rkt b/collects/lazy/lazy-tool.rkt
index e65c260853..8dadeb65c0 100644
--- a/collects/lazy/lazy-tool.rkt
+++ b/collects/lazy/lazy-tool.rkt
@@ -1,17 +1,18 @@
-#lang racket
+#lang racket/base
 
-(require string-constants
+(require racket/unit
+         racket/class
+         string-constants
          drracket/tool
          lang/stepper-language-interface)
 
 (provide tool@)
 
 (define tool@
-  (unit 
+  (unit
     (import drracket:tool^)
     (export drracket:tool-exports^)
 
-
     (define (stepper-settings-language %)
       (if (implementation? % stepper-language<%>)
           (class* % (stepper-language<%>)
@@ -50,13 +51,12 @@
 ;      (equal? (drracket:language:simple-settings->vector s)
 ;              (drracket:language:simple-settings->vector (default-settings))))
         (super-new)))
-    
-      
+
     (define (phase1) (void))
-    
+
     ;; phase2 : -> void
     (define (phase2)
-      
+
       (define lazy-language%
         (stepper-settings-language
          ((drracket:language:get-default-mixin)
@@ -64,7 +64,7 @@
            (module-based-language-extension
             (drracket:language:simple-module-based-language->module-based-language-mixin
              drracket:language:simple-module-based-language%))))))
-      
+
       (drracket:language-configuration:add-language
        (instantiate lazy-language% ()
          (one-line-summary "Lazy Racket")
diff --git a/collects/mrlib/private/regmk.rkt b/collects/mrlib/private/regmk.rkt
index bf5d8bf1ff..a6401351ca 100644
--- a/collects/mrlib/private/regmk.rkt
+++ b/collects/mrlib/private/regmk.rkt
@@ -1,6 +1,9 @@
-#lang racket
+#lang racket/base
+
+(require (for-syntax racket/base))
+
 (provide define-struct/reg-mk
-         id->constructor 
+         id->constructor
          (struct-out point)
          (struct-out bb))
 
diff --git a/collects/racket/math.rkt b/collects/racket/math.rkt
index f4c37709a0..c607a0765a 100644
--- a/collects/racket/math.rkt
+++ b/collects/racket/math.rkt
@@ -1,5 +1,4 @@
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;
 ;; math.rkt: some extra math routines
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
diff --git a/collects/setup/collects.rkt b/collects/setup/collects.rkt
index 31c5c7d6fc..45dd7b208b 100644
--- a/collects/setup/collects.rkt
+++ b/collects/setup/collects.rkt
@@ -1,8 +1,7 @@
-#lang racket  
+#lang racket/base
 
 (provide (struct-out cc))
 
 (define-struct cc
   (collection path name info omit-root info-root info-path info-path-mode shadowing-policy)
   #:inspector #f)
-
diff --git a/collects/srfi/19/time.rkt b/collects/srfi/19/time.rkt
index a37fac7036..37adbf89f6 100644
--- a/collects/srfi/19/time.rkt
+++ b/collects/srfi/19/time.rkt
@@ -1,7 +1,7 @@
-#lang racket
+#lang racket/base
 
 ;;;
-;;; <time.ss> ---- SRFI 19 Time Data Types and Procedures port to PLT Scheme
+;;; <time.ss> ---- SRFI 19 Time Data Types and Procedures port to Racket
 ;;; Time-stamp: <2004-07-21 12:57:06 solsona>
 ;;;
 ;;; Usually, I would add a copyright notice, and the announce that
@@ -60,7 +60,7 @@
 ;; -- Multiple helper procedures. TM:xxx procedures are meant to be
 ;; internal.
 
-(require scheme/serialize
+(require racket/serialize
          srfi/8/receive
          srfi/29
          srfi/optional)
@@ -77,12 +77,12 @@
          ;; Time arithmetic
          time-difference time-difference! add-duration add-duration! subtract-duration subtract-duration!
          ;; Date object and accessors
-         ;; date structure is provided by core PLT Scheme, we just extended tu support miliseconds:
+         ;; date structure is provided by core Racket, we just extended tu support miliseconds:
          srfi:make-date srfi:date?
          deserialize-info:tm:date-v0
          date-nanosecond srfi:date-second srfi:date-minute srfi:date-hour srfi:date-day srfi:date-month
          srfi:date-year date-zone-offset
-         ;; This are not part of the date structure (as they are in the original PLT Scheme's date)
+         ;; This are not part of the date structure (as they are in the original Racket's date)
          srfi:date-year-day srfi:date-week-day date-week-number
          
          ;; The following procedures work with this modified version.
@@ -643,7 +643,7 @@
                     (tm:set-date-year!        d1 (srfi:date-year   d0))
                     (tm:set-date-zone-offset! d1 (date-zone-offset d0))))))))
 
-;; PLT Scheme date structure has the following:
+;; Racket's date structure has the following:
 ;;   * second : 0 to 61 (60 and 61 are for unusual leap-seconds)
 ;;   * minute : 0 to 59
 ;;   * hour : 0 to 23
diff --git a/collects/test-engine/racket-tests.rkt b/collects/test-engine/racket-tests.rkt
index 822b1c01b5..dfaf02c170 100644
--- a/collects/test-engine/racket-tests.rkt
+++ b/collects/test-engine/racket-tests.rkt
@@ -1,14 +1,14 @@
-#lang racket
+#lang racket/base
 
 (require lang/private/teachprims
-         (for-syntax lang/private/rewrite-error-message)
-         scheme/class
-         scheme/match
-	 lang/private/continuation-mark-key         
+         (for-syntax racket/base
+                     lang/private/rewrite-error-message)
+         racket/class
+         racket/match
+         lang/private/continuation-mark-key
          lang/private/rewrite-error-message
-         (only-in scheme/base for memf findf)
          "test-engine.rkt"
-	 "test-info.scm")
+         "test-info.scm")
 
 (require (for-syntax stepper/private/syntax-property))
 
@@ -72,7 +72,7 @@
       #`(define #,bogus-name
           #,(stepper-syntax-property
              #`(let ([test-engine (namespace-variable-value
-				   'test~object #f builder (current-namespace))])
+                                   'test~object #f builder (current-namespace))])
                  (when test-engine
                    (insert-test test-engine
                                 (lambda ()