diff --git a/src/ikarus.boot b/src/ikarus.boot
index 0ebdb36..8577b43 100644
Binary files a/src/ikarus.boot and b/src/ikarus.boot differ
diff --git a/src/ikarus.io.input-strings.ss b/src/ikarus.io.input-strings.ss
index 2cc2a43..4e9bf76 100644
--- a/src/ikarus.io.input-strings.ss
+++ b/src/ikarus.io.input-strings.ss
@@ -1,5 +1,35 @@
 
-#error not yet
+(library (ikarus io input-strings)
+  (export open-input-string)
+  (import 
+    (ikarus system $strings)
+    (ikarus system $fx)
+    (ikarus system $pairs)
+    (ikarus system $ports)
+    (ikarus system $io)
+    (except (ikarus) open-input-string))
+ 
+  (define-syntax message-case
+    (syntax-rules (else)
+      [(_ msg args 
+          [(msg-name msg-arg* ...) b b* ...] ... 
+          [else else1 else2 ...])
+       (let ([tmsg msg] [targs args])
+         (define-syntax match-and-bind
+           (syntax-rules ()
+             [(__ y () body)
+              (if (null? y) 
+                  body
+                  (error 'message-case "unmatched ~s" (cons tmsg targs)))]
+             [(__ y (a a* (... ...)) body)
+              (if (pair? y)
+                  (let ([a (car y)] [d (cdr y)])
+                    (match-and-bind d (a* (... ...)) body))
+                  (error 'message-case "unmatched ~s" (cons tmsg targs)))]))
+         (case tmsg
+           [(msg-name) 
+            (match-and-bind targs (msg-arg* ...) (begin b b* ...))] ...
+           [else else1 else2 ...]))]))
 
   (define make-input-string-handler
     (lambda (str)
@@ -55,4 +85,5 @@
                     (make-input-string-handler str)
                     str)])
         port)))
+  )
 
diff --git a/src/makefile.ss b/src/makefile.ss
index e6f2dcc..44255f4 100755
--- a/src/makefile.ss
+++ b/src/makefile.ss
@@ -43,6 +43,7 @@
     "ikarus.io-primitives.ss"
     "ikarus.io.input-files.ss"
     "ikarus.io.output-files.ss"
+    "ikarus.io.input-strings.ss"
     "ikarus.io.output-strings.ss"
     "ikarus.hash-tables.ss"
     "ikarus.writer.ss"
@@ -334,6 +335,7 @@
     [with-output-to-file     i r]
     [open-output-file        i r]
     [open-output-string      i]
+    [open-input-string       i]
     [get-output-string       i]
     [with-output-to-string   i]
     [close-input-port        i r]