This is a version of Mike Whitbeck's React 3.2 program compiled for OS/2 versions 2 and above. It calculates concentration vs. time profiles for specified chemical mechanisms, and will fit model rate coefficients to data if available. This program is similar to the Macintosh version which is also available at www.ccl.net in /pub/chemistry/software/mac. I recommend the program kit (react32os2.zip) be placed in pub/chemistry/software/os-2.