diff --git a/scheme/ikarus.not-yet-implemented.ss b/scheme/ikarus.not-yet-implemented.ss
index ad4fd4e..5c2b40f 100644
--- a/scheme/ikarus.not-yet-implemented.ss
+++ b/scheme/ikarus.not-yet-implemented.ss
@@ -1,7 +1,7 @@
 
 (library (ikarus not-yet-implemented)
   (export 
-    angle make-polar 
+    make-polar 
     bitwise-copy-bit-field bitwise-reverse-bit-field
     bitwise-rotate-bit-field bitwise-if fxreverse-bit-field
     fxrotate-bit-field 
@@ -17,7 +17,7 @@
     string-upcase)
 
   (import (except (ikarus) 
-    angle make-polar 
+    make-polar 
     bitwise-copy-bit-field bitwise-reverse-bit-field
     bitwise-rotate-bit-field bitwise-if fxreverse-bit-field
     fxrotate-bit-field 
@@ -57,7 +57,7 @@
   (not-yet 
     ;;; should be implemented
     string-downcase string-titlecase string-upcase
-    angle make-polar 
+    make-polar 
     bitwise-if
     bitwise-rotate-bit-field bitwise-copy-bit-field bitwise-reverse-bit-field
     fxreverse-bit-field fxrotate-bit-field 
diff --git a/scheme/ikarus.numerics.ss b/scheme/ikarus.numerics.ss
index 4604e8b..a46bff6 100644
--- a/scheme/ikarus.numerics.ss
+++ b/scheme/ikarus.numerics.ss
@@ -3619,10 +3619,10 @@
 
 (library (ikarus complex-numbers)
   (export make-rectangular $make-rectangular
-          real-part imag-part magnitude)
+          real-part imag-part angle magnitude)
   (import 
     (except (ikarus)
-      make-rectangular real-part imag-part magnitude)
+      make-rectangular real-part imag-part angle magnitude)
     (except (ikarus system $compnums) $make-rectangular))
 
   (define ($make-rectangular r i)
@@ -3667,6 +3667,35 @@
         [else 
          (die 'magnitude "not a number" x)])))
 
+  (define angle
+    (lambda (x)
+      (import (ikarus system $bignums) (ikarus system $ratnums))
+      (define PI (acos -1))
+      (cond
+        [(fixnum? x)
+         (if (fx>? x 0)
+             0
+             (if (fx<? x 0)
+                 PI
+                 (die 'angle "undefined for 0")))]
+        [(bignum? x)
+         (if ($bignum-positive? x) 0 PI)]
+        [(ratnum? x)
+         (let ([n ($ratnum-n x)])
+           (if (> n 0) 0 PI))]
+        [(flonum? x)
+         (atan 0.0 x)]
+        [(compnum? x)
+         (let ([r ($compnum-real x)]
+               [i ($compnum-imag x)])
+           (atan i r))]
+        [(cflonum? x)
+         (let ([r ($cflonum-real x)]
+               [i ($cflonum-imag x)])
+           (atan i r))]
+        [else 
+         (die 'angle "not a number" x)])))
+
   (define real-part
     (lambda (x)
       (cond
diff --git a/scheme/last-revision b/scheme/last-revision
index 07b0f42..576784f 100644
--- a/scheme/last-revision
+++ b/scheme/last-revision
@@ -1 +1 @@
-1537
+1538