In 1975, soon after he left college and as the first microcomputers became available, Alan Cooper founded his first company, Structured Systems Group (SSG), in Oakland, California, which became one of the first microcomputer software companies. SSG's software accounting product, General Ledger, was sold through ads in popular magazines such as "Byte" and "Interface Age". This software was, according to the historical account in Fire in the Valley (by Paul Freiberger and Michael Swaine), “probably the first serious business software for microcomputers.” It was both the start of Cooper's career as a software author and the beginning of the microcomputer software business. Ultimately, Cooper developed a dozen original products at Structured Systems Group before he sold his interest in the company in 1980.