Univac Corporation (now Unisys) has been an innovator in computer systems since the early 1960s. Univac (then Remington Rand), built the first commercial computer, the Univac I. This volume continues the story of Univac (later Unisys) computer systems from the Univac 1105. Its successors-the early Univac 1100 machines-helped to establish the concept of a family of computer systems. It was one of the first to develop and deploy a multidimensional operating system that supported interactive, real-time, and batch processing. Ease of access and operation in all modes was especially attractive to scientific and academic communities. It was instrumental in developing COBOL and DMS-1100 for business data processing. The upward compatibility of the Univac 1100 series machines from the Univac 1107 to the Sperry 2200 series demonstrated how evolutionary development could protect its customer’s investment while continually enhancing performance. As one of the founders of the computing industry, Univac has survived over 60 years of expansion and consolidation to survive as part of Unisys as one of the two remaining mainframe manufacturers.