This book surveys the history of the Burroughs Corporation, from its earliest days as a computer system vendor up to the late 1990s after its merger with Univac Corporation to form Unisys. The Burroughs Corporation was one of the earliest manufacturers of large mainframe computers through its purchase of Datatron. Burroughs developed four more generations of mainframe computer systems, culminating in the B2x00/3x00/4x00 family of machines. It also developed one of the most innovative computer architectures in the B5x00/6x00/7x00 family. These systems featured direct execution of high-level language programs, stack-based and tagged architectures, multiprocessing, and early virtualization through descriptors. Burroughs’ early work on the ILLIAC IV led to the development of the D825 for SAGE and the B8500, the former a notable success and the latter less than successful. Burroughs’ foray into small computer systems was not financially viable, but its merger with Univac led to the formation of Unisys, where its advanced architectures survive today as counterpoints to IBM’s mainframe architectures—the two surviving manufacturers from the mainframe era.