The saga of the computing industry is rich with outsize characters and surprising plot turns, but there's one story that has risen over time to mythic proportions. It's the tale of how software pioneer Gary Kildall missed out on the opportunity to supply IBM with the operating system for its first PC -- essentially handing the chance of a lifetime, and control of tech's future, to rival Bill Gates and Microsoft Corp. In the process, he may have missed out on becoming the world's richest man.

The legend goes like this: One fateful day in the summer of 1980, three buttoned-down IBMers called on a band of hippie programmers at Digital Research Inc. located in Pacific Grove, Calif. They hoped to discuss licensing DRI's industry-leading operating system, CP/M. Instead, DRI founder Gary Kildall blew off IBM to gallivant around in his airplane, and the frustrated IBMers turned to Gates for their operating system. This anecdote has been told so often that techies need only be reminded of "the day Gary Kildall went flying" to recall the rest. While he's revered for his technical innovations, many believe Kildall made one of the biggest mistakes in the history of commerce.

But what if that's not what happened? What if IBM and Microsoft deprived Kildall not only of untold riches but also of the credit for a seminal role in the PC revolution? That's the thesis of a chapter about Kildall in They Made America, a serious coffee table history book by renowned author and former newspaper editor Harold Evans. The book, published by Little Brown on Oct. 12, profiles 70 American innovators and is the inspiration for an upcoming PBS series. And while other tech authors have debunked the gallivanting story before, Evans bases his Kildall chapter on a 226-page, never-published memoir written by Kildall just before his death in 1994. Early on, Kildall seemed to represent the best hopes of the nascent computer industry. But by the time he died at age 52, after falling in a tavern, he had become embittered and struggled with alcohol.

They Made America is certain to elicit cries of protest. That's because it attacks the reputations of some of the key players of the early PC era -- Gates, IBM, and Tim Paterson, the Seattle programmer who wrote an operating system, QDOS, based partly on CP/M that became Microsoft's DOS. Evans asserts that Paterson copied parts of CP/M and that IBM tricked Kildall. Because Gates rather than the more innovative Kildall prevailed, according to the book, the world's PC users endured "more than a decade of crashes with incalculable economic cost in lost data and lost opportunities." David G. Lefer, one of Evans' two collaborators, says: "We're trying to set the record straight. Gates didn't invent the PC operating system, and any history that says he did is wrong."

There's no doubt that Kildall was one of the pioneers of the industry. He invented the first operating system for microcomputers in the early 1970s, making it possible for hobbyists and companies to build the first personal computers. Legalities aside, Microsoft's original DOS was based in part on Kildall's CP/M. His insight was that by creating an operating system separate from the hardware, applications could run on computers that were made by different manufacturers. "What really drove Gary was inventing things," says friend and former DRI executive Tom Rolander in an interview with BusinessWeek.