Make no mistake--some crime pays. Handsomely. The average haul for computer-related bank frauds and embezzlements amounted to a nifty $430,000, according to one independent study Whiteside cites. Fiddling with the input is the usual method, but Whiteside can point to instances where the computer terminal was never approached. One fellow simply coded blank deposit slips with his account number, then replaced them neatly. And sat back to watch the moola roll in! But Whiteside's raffish little round-up of computer capers--including the ingenious data-processing which wafted 217 boxcars from the defunct Penn Central Railway--has a more serious purpose. Experts have shown that even the most ""secure"" computer systems designed by the Defense Department for top secret information are vulnerable to penetration. Encoded passwords can't keep out saboteurs or criminals. Pointing out that thus far the law has been lenient when not actually impotent in dealing with tamperers (they're usually very white-collar), Whiteside includes in an appendix the text of Sen, Abraham Ribicoff's bill, introduced last year, providing harsh sentences and heavy fines for those who manipulate computer data for any illegal purpose whatever. If this is indeed the crime wave of the future, Whiteside's easy-to-read, jargon-free little book will clue you in.