diff --git a/ChangeLog b/ChangeLog
index fd03b2b..bb65336 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2019-06-05         Arnold D. Robbins     <arnold@skeeve.com>
+
+	* b.c (relex): Count parentheses and treat umatched right paren
+	as a literal character.
+	* awktest.tar (testdir/T.re): Added a test case.
+	* main.c (version): Upated.
+
 2019-05-29         Arnold D. Robbins     <arnold@skeeve.com>
 
 	* lib.c (isclvar): Remove check for additional '=' after
diff --git a/FIXES b/FIXES
index 183eaed..0665229 100644
--- a/FIXES
+++ b/FIXES
@@ -25,6 +25,12 @@ THIS SOFTWARE.
 This file lists all bug fixes, changes, etc., made since the AWK book
 was sent to the printers in August, 1987.
 
+June 5, 2019:
+	Allow unmatched right parenthesis in a regular expression to
+	be treated literally. Fixes Issue #40. Thanks to GitHub user
+	Warner Losh (bsdimp) for the report. Thanks to Arnold Robbins
+	for the fix.
+
 May 29,2019:
 	Fix check for command line arguments to no longer require that
 	first character after '=' not be another '='. Reverts change of
@@ -34,7 +40,7 @@ May 29,2019:
 Apr 7, 2019:
 	Update awktest.tar(p.50) to use modern options to sort. Needed
 	for Android development. Thanks to GitHub user mohd-akram (Mohamed
-	Akram).  From Comment #33.
+	Akram).  From Issue #33.
 
 Mar 12, 2019:
 	Added very simplistic support for cross-compiling in the
@@ -54,7 +60,7 @@ Mar 3, 2019:
 	#12: Avoid undefined behaviour when using ctype(3) functions in
 	     relex(). Thanks to GitHub user iamleot.
 	#31: Make getline handle numeric strings, and update FIXES. Thanks
-	     to GitHub user arnoldrobbins
+	     to GitHub user arnoldrobbins.
 	#32: maketab: support build systems with read-only source. Thanks
 	     to GitHub user enh.
 
diff --git a/awktest.tar b/awktest.tar
index 4ca482a..011c073 100644
Binary files a/awktest.tar and b/awktest.tar differ
diff --git a/b.c b/b.c
index 37ea0a5..2eeba2a 100644
--- a/b.c
+++ b/b.c
@@ -912,6 +912,7 @@ int relex(void)		/* lexical analyzer for reparse */
 	int i;
 	int num, m, commafound, digitfound;
 	const uschar *startreptok;
+	static int parens = 0;
 
 rescan:
 	starttok = prestr;
@@ -925,9 +926,18 @@ rescan:
 	case '\0': prestr--; return '\0';
 	case '^':
 	case '$':
-	case '(':
-	case ')':
 		return c;
+	case '(':
+		parens++;
+		return c;
+	case ')':
+		if (parens) {
+			parens--;
+			return c;
+		}
+		/* unmatched close parenthesis; per POSIX, treat as literal */
+		rlxval = c;
+		return CHAR;
 	case '\\':
 		rlxval = quoted(&prestr);
 		return CHAR;
diff --git a/main.c b/main.c
index 98661fc..2d7a382 100644
--- a/main.c
+++ b/main.c
@@ -22,7 +22,7 @@ ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
 THIS SOFTWARE.
 ****************************************************************/
 
-const char	*version = "version 20190529";
+const char	*version = "version 20190605";
 
 #define DEBUG
 #include <stdio.h>