diff --git a/lens/applicable.rkt b/lens/applicable.rkt
index 78e233d..bcd4bca 100644
--- a/lens/applicable.rkt
+++ b/lens/applicable.rkt
@@ -1,4 +1,4 @@
-#lang racket
+#lang racket/base
 
 (provide (all-from-out "main.rkt"))
 
diff --git a/lens/base/identity.rkt b/lens/base/identity.rkt
index 2ce5710..18e2db1 100644
--- a/lens/base/identity.rkt
+++ b/lens/base/identity.rkt
@@ -1,6 +1,6 @@
-#lang racket
+#lang racket/base
 
-(require "base.rkt")
+(require racket/function racket/contract/base "base.rkt")
 
 (module+ test
   (require rackunit
diff --git a/lens/base/main.rkt b/lens/base/main.rkt
index b7a4ab3..fcec7c2 100644
--- a/lens/base/main.rkt
+++ b/lens/base/main.rkt
@@ -1,4 +1,4 @@
-#lang racket
+#lang racket/base
 
 (require "base.rkt"
          "view-set.rkt"
diff --git a/lens/base/transform.rkt b/lens/base/transform.rkt
index adcb808..3217eb7 100644
--- a/lens/base/transform.rkt
+++ b/lens/base/transform.rkt
@@ -1,11 +1,14 @@
-#lang racket
+#lang racket/base
 
 (require unstable/sequence
+         racket/match
+         racket/contract/base
          "base.rkt"
          "../util/list-pair-contract.rkt")
 
 (module+ test
   (require rackunit
+           racket/list
            fancy-app))
 
 (provide
diff --git a/lens/base/view-set.rkt b/lens/base/view-set.rkt
index 4f5ef2a..02d39af 100644
--- a/lens/base/view-set.rkt
+++ b/lens/base/view-set.rkt
@@ -1,12 +1,14 @@
-#lang racket
+#lang racket/base
 
 (require unstable/sequence
+         racket/match
+         racket/contract/base
          fancy-app
          "base.rkt"
          "../util/list-pair-contract.rkt")
 
 (module+ test
-  (require rackunit))
+  (require rackunit racket/list))
 
 (provide
  lens-view
diff --git a/lens/hash/nested.rkt b/lens/hash/nested.rkt
index 5a89596..e19cc8e 100644
--- a/lens/hash/nested.rkt
+++ b/lens/hash/nested.rkt
@@ -1,6 +1,7 @@
-#lang racket
+#lang racket/base
 
-(require "../base/main.rkt"
+(require racket/contract/base
+         "../base/main.rkt"
          "../compound/main.rkt"
          "../util/immutable.rkt"
          "../util/rest-contract.rkt"
diff --git a/lens/list/assoc.rkt b/lens/list/assoc.rkt
index db223b7..5114ff6 100644
--- a/lens/list/assoc.rkt
+++ b/lens/list/assoc.rkt
@@ -1,5 +1,6 @@
-#lang racket
+#lang racket/base
 
+(require racket/contract/base)
 (provide (contract-out
           [assoc-lens
            (->* (any/c) (#:is-equal? (-> any/c any/c boolean?))
@@ -10,8 +11,7 @@
            (-> any/c (lens/c (listof pair?) any/c))]
           ))
 
-(require racket/list
-         fancy-app
+(require fancy-app
          "../base/main.rkt")
 
 (module+ test
diff --git a/lens/list/car-cdr.rkt b/lens/list/car-cdr.rkt
index 06f030a..f0d89c5 100644
--- a/lens/list/car-cdr.rkt
+++ b/lens/list/car-cdr.rkt
@@ -1,5 +1,6 @@
-#lang racket
+#lang racket/base
 
+(require racket/contract/base)
 (provide
  (contract-out [car-lens (lens/c pair? any/c)]
                [cdr-lens (lens/c pair? any/c)]))
diff --git a/lens/list/list-ref-take-drop.rkt b/lens/list/list-ref-take-drop.rkt
index 73f66eb..d0c5517 100644
--- a/lens/list/list-ref-take-drop.rkt
+++ b/lens/list/list-ref-take-drop.rkt
@@ -1,5 +1,6 @@
-#lang racket
+#lang racket/base
 
+(require racket/contract/base)
 (provide
  (contract-out
   [list-ref-lens
diff --git a/unstable/lens.rkt b/unstable/lens.rkt
index cd8c177..fe7735c 100644
--- a/unstable/lens.rkt
+++ b/unstable/lens.rkt
@@ -1,4 +1,4 @@
-#lang racket
+#lang racket/base
 
 (require "lens/main.rkt")
 
diff --git a/unstable/lens/syntax.rkt b/unstable/lens/syntax.rkt
index 5bc3f6a..ac00bf2 100644
--- a/unstable/lens/syntax.rkt
+++ b/unstable/lens/syntax.rkt
@@ -1,4 +1,4 @@
-#lang racket
+#lang racket/base
 
 (require "syntax/syntax.rkt"
          "syntax/syntax-keyword.rkt")
diff --git a/unstable/lens/syntax/syntax-keyword.rkt b/unstable/lens/syntax/syntax-keyword.rkt
index 59112ac..6aff43e 100644
--- a/unstable/lens/syntax/syntax-keyword.rkt
+++ b/unstable/lens/syntax/syntax-keyword.rkt
@@ -1,6 +1,7 @@
-#lang racket
+#lang racket/base
 
 (require lens
+         racket/contract/base
          fancy-app
          syntax/parse)
 
diff --git a/unstable/lens/syntax/syntax.rkt b/unstable/lens/syntax/syntax.rkt
index d71f5b9..c7a7320 100644
--- a/unstable/lens/syntax/syntax.rkt
+++ b/unstable/lens/syntax/syntax.rkt
@@ -1,9 +1,10 @@
-#lang racket
+#lang racket/base
 
 (require syntax/parse
          rackunit
          lens
-         (for-syntax racket/syntax
+         (for-syntax racket/base
+                     racket/syntax
                      syntax/stx
                      syntax/parse))
 
diff --git a/unstable/lens/tests/doc-coverage.rkt b/unstable/lens/tests/doc-coverage.rkt
index 46159f5..f0ed18f 100644
--- a/unstable/lens/tests/doc-coverage.rkt
+++ b/unstable/lens/tests/doc-coverage.rkt
@@ -1,4 +1,4 @@
-#lang racket
+#lang racket/base
 
 (module+ test
   (require doc-coverage
diff --git a/unstable/lens/view-set.rkt b/unstable/lens/view-set.rkt
index e0c1519..0e9c382 100644
--- a/unstable/lens/view-set.rkt
+++ b/unstable/lens/view-set.rkt
@@ -1,6 +1,7 @@
-#lang racket
+#lang racket/base
 
 (require lens
+         racket/contract/base
          fancy-app)
 
 (module+ test