Back in 1888, Walter Jessurun had a great idea for a product. To make a retail business grow, he realized, you had to be able to compare today's volume of business with what you did yesterday, what you did on this day a year ago, what you did two years ago, and so on. So why not produce and sell a notebook that would help retailers do that? He proceeded to design a little black manual in which customers could enter daily revenues (and thus make day-to-day comparisons) for up to six years. He called the manual Beat Yesterday.

Since then, Beat Yesterday has become a staple of retailers, used everywhere from McDonald's to Sears to Benetton. It is still put out by the Jessurun family business, Sales Record Publishing Co., in Pomfret, Conn., which has by and large left the marketing to word-of-mouth. That has worked pretty well. Thus, for example, cook-ware marketer Williams-Sonoma Inc. started using Beat Yesterday on the recommendation of board members from Bullock's and Neiman-Marcus. Such referrals have helped keep Sales Record in the black for decades. The company currently earns approximately $70,000 per year on sales of some $250,000, with only three full-time employees, all of them Jessuruns.

Yet, oddly enough, the family has never taken its own advice and tried to beat yesterday -- until now, that is. Company vice-president Brian Jessurun, Walter's grandson, wants to triple the company's revenues over the next five years. Toward that end, he has begun advertising in trade journals and thinking about new products. One possibility is a computerized version of Beat Yesterday; another is a deluxe executive model that would sell for $100 (versus the standard $15).

Not that he's getting carried away. The company, which subcontracts its manufacturing, has never hired outsiders, and young Jessurun, 28, doesn't plan to start. "This is going to be a family business no matter what," he says, "even if it means I have to have kids."