When Leonard A. Fish peers into the not-too-distant future, there are things he sees, and things he doesn't see. What he doesn't see are cashiers, the flesh-and-blood front line of retailing. In their place, he envisions an army of "retail robots" effortlessly taking cash, making change, and beeping "Have a nice day."

Fish is an inventor who numbers an early automated teller machine (ATM) and something called Silly String among his creations. The latter he describes as a "mean-little-kid-type" novelty item: It came in a spray can, and, when you pressed the button, a colored, semiliquid plastic came out, hardening on anything it touched. Not one to rest on his laurels, Fish is now working on a project that he believes will revolutionize retailing -- namely, the development of a computerized clerk. He has already conquered what may be the biggest technological obstacle, having created a device that can accept any currency denomination, telling the difference between a $5 bill and a $50, while spotting the illegal tender.

"This is difficult because denominations of U.S. currency are all the same color and size," explains Fish, 48. "Not only that, but the dollars are often torn, beaten up, and dirty. You need a machine that can check many different points on a bill to figure out what the denomination is, and whether or not it is counterfeit."

His solution involves sophisticated scanners that check about 6,000 verification points on each inserted bill. He has used that technology in two models of automated change-makers that his company -- Currency Technology Corp. of Schiller Park, Ill. -- is marketing to casino and video arcade operators. The casino version, which changes bills as large as a hundred, sells for $35,000, while the video arcade version tops out at a twenty and goes for $3,000.

But Fish is after bigger game. He sees a souped-up version of his bill-reading change-maker stepping into almost every spot now occupied by a living, breathing retail clerk. In a supermarket, it could be tied in to the universal price code scanner. In a gas station, it could work off the pump, taking cash or credit cards. In the post office, it could sell the proper postage for letters and packages.

The savings could be enormous, although there may still be a few bugs to work out. "A supermarket's biggest expense is payroll. That's what keeps prices high, not shoplifting, which seems to be the major objection to robots," Fish says. "People say a customer would walk right through the line. But now that we have bar-coded products, the bagger, who's only paid minimum wage, could just keep an ear cocked for the sound of the beep. If he doesn't hear it, he just politely asks the customer to pass the product over the sensor again."

In any event, Fish pooh-poohs charges that his change-makers and robots will put people on the unemployment line. "My inventions supplement people, they don't replace them," he says "And anyway, who wants to be a change person in a casino? They'd rather be manning the blackjack table."