They called him "Mister Red Book." But Richard Sperry Yeoman did more than just write the best-selling coin book in history. He rewrote the history of the coin collecting hobby - transforming numismatics from a pastime of the scholarly and wealthy to a passionate pursuit of ordinary, everyday Americans.

R.S. Yeoman died on Nov. 9, 1988, at the age of 84, after suffering a stroke while driving his car near his retirement home in Tucson, Ariz. But the legacy he left is a towering testimonial to the quiet dedication of his long and fruitful life.

Yeoman never regarded himself as the giant he truly was. Indeed, he seemed embarrassed by the kudos he received - and his self-effacing manner endeared him all the more to those of us who had the good fortune to know him. But while he was reluctant to talk of his achievements, his record speaks quite eloquently for itself. The Whitman folder ... the Blue Book ... the Red Book ... the Brown Book - these and other accomplishments stand as impressive monuments to his service.

Dick Yeoman would often deflect admirers' compliments by saying he'd simply been lucky - a man who merely chanced to be "in the right place at the right time." The place was the Whitman Publishing Co. in Racine, Wisconsin, and the time was 1934. Yeoman was a young sales and advertising executive and got the assignment to market a new product: an 11-by-14-inch cardboard chart with rows of holes designed to hold and display various U.S. coins by date and mint mark.

This "coin board" had been devised by a man named J.K. Post. But Yeoman was the one who promoted it and expanded it from just a novelty item to the cornerstone of what became a coin collecting industry.

In 1940, Yeoman hit upon a method of improving the basic coin board: He reduced its size, added extra pages and a flap and came up with the Whitman folder. These simple yet ingenious modifications gave the coins more protection and, at the same time, made it far easier to store them and carry them around.

Though modest about his role in developing and popularizing these products, Yeoman readily acknowledged the importance of the "penny board" in stimulating the modern coin market.

"The system of collecting by dates and mint marks made all the difference in the world," he later observed. "The idea of filling holes one by one until the collector had put together a complete set - this had tremendous impact upon the American public.

"This wasn't really a numismatic item, but it started millions of collectors."

Many of the collectors created by the coin boards and folders soon became curious as to how much their coins were worth. Yeoman and Whitman satisfied that curiosity in 1942 with the first edition of the "Handbook of United States Coins," or "Blue Book," as it's almost universally known. This gave wholesale prices - the prices a collector could expect to receive for his coins from a dealer.

"A Guide Book of United States Coins" - better known as the "Red Book" - was scheduled to join the Blue Book not long afterward, this time providing retail values. But World War II delayed the book's debut for five years. When it did appear, it proved to be an even bigger seller. Both books, in fact, rank today among the all-time nonfiction best-sellers, with total combined sales in the tens of millions.

The "Brown Book" - "A Catalog of Modern World Coins" - followed some years later, as did several other R.S. Yeoman books.

The coin boards, folders and books spawned a major department at Whitman, with Yeoman as its head. He retired in 1969, but continued his relationship thereafter as a consultant.

Dick attended coin shows every now and then after his retirement, and seeing him was always a special pleasure. I saw him for the final time at the 1987 convention of the American Numismatic Association in Atlanta and welcomed the chance to get his observations on the changing hobby scene.

Though the hobby of the Eighties was altogether different from the one he first encountered in the Thirties, Dick Yeoman remained an astute coin market analyst to the end. In a 1984 interview, for example, he pinpointed one of our major problems while discussing the U.S. Mint's Los Angeles Olympic coin program.

"What we really need to draw new collectors," he commented, "is not a $350 gold coin but a part-silver coin selling for, say, $5. The government needs to come down to the Boy Scout level - to a price where a grandfather might buy such a coin for his grandchildren. If we could get commemorative coins priced at no more than $5, we'd really stir things up."

I suspect that Dick would not be too happy with the continuing proliferation of high-priced U.S. commemorative coins we have seen in the decade since his death. On the other hand, he would have welcomed the 50-state program of circulating commemoratives due to debut next year.

Although Dick Yeoman saw room for improvement, he felt that on the whole, coin collecting was healthy in the Eighties.

"The interest is there," he remarked to me at the time. "Nobody can tell me that it's dead. It's quieter; there's more concern today about security, so many collectors are going about it now more discreetly. They're still enjoying it, though. They're still there."

"Yeoman" was a pen name; Dick's real name was "Yeo." The name fit him perfectly, though.