The development of the computing industry in Minnesota has been largely undocumented, despite the fact that from the late 1940s through the late 1980s, the state was home to one of the premier computing industry clusters, with firms such as Control Data, Honeywell, Sperry Univac, and IBM and a number of component suppliers and ancillary industries. Thomas J. Misa skillfully remedies this lacuna with his carefully researched book, Digital State, which is a must-read for anyone interested in the history—and geography—of computing systems.

Misa begins with computing developments at the University of Pennsylvania in the 1940s and the acquisition by Remington Rand of J. Presper Eckert and John Mauchly's failing university computer spinoff, Eckert-Mauchly Computer Company. Roughly contemporaneously, in Minneapolis a new firm, Engineering Research Associates (ERA), was formed by Howard Engstrom and William C. Norris to conduct defense-related cryptographic analysis. In the late 1940s, ERA, funded by government contracts, began building computers. The level of detail in Misa's analysis is remarkable. For example, he documents how ERA's need for magnetic coating for memory drums encouraged 3M to expand into magnetic data storage, thus contributing to the formation of its expertise in the field. However, ERA suffered from weak financial performance and in 1952 was purchased by the Connecticut firm Remington Rand. In 1955, Sperry Corporation, an electronics and precision instruments firm, merged with Remington Rand. The new Sperry Rand now had significant computer operations in Minnesota and produced many of the Univac series of computers there.

In 1957, a group of Univac employees—led by ERA veterans including Norris and Seymour C. Cray—established a new firm, Control Data Corporation (CDC); it was enormously successful and eventually became the central firm in Minnesota's computer industry cluster. CDC went on to build a family of computers, but it was known in particular for its “supercomputers.” As an integrated manufacturer, CDC also built many of the key components, including disk drives. CDC was the entrepreneurial face of the local computing industry. Not surprisingly for such a successful company, CDC was the origin of many spin-off firms that also operated locally.

In addition to CDC, Univac, and related firms, Minnesota was also home to Honeywell, an industrial controls manufacturer that diversified into computing and became an important mainframe competitor. In 1956, New York–based IBM built what would become one of its largest manufacturing and development facilities in Rochester, Minnesota. Given that Minnesota hosted one of IBM's largest facilities and the operations of three of its largest competitors, it would not be an exaggeration to suggest that Minnesota was the center of the U.S. mainframe computing industry. The Minnesota state government and the University of Minnesota recognized the importance of the computing industry cluster and developed policies and programs to assist its growth. In the 1990s, as the mainframe market collapsed, the local industry also collapsed.

Misa begins the book by discussing the creation and growth of industrial clusters and lamenting that the history of Minnesota's computing cluster is little known. He painstakingly describes the evolution of the Minnesota industry, documenting the growth and management changes in its firms. In this respect, the book is a research tour de force.

Yet those interested in the evolution and eventual demise of regional industry will search in vain for any detailed discussion of the reasons Minnesota is no longer significant as a computer industry center. Why did all the firms decline? It may not have been predetermined, as Misa indicates Minnesotan firms were early pioneers in time sharing. In 1974, one of the first computer networking firms, the Minnesota-based Network Systems Corporation (NSC), was founded by ex-CDC employees. But, even though NSC had superior technology and was early to market, it never transitioned to the distributed computing paradigm pioneered in Silicon Valley and Boston. After missing this transition, NSC languished, was bought by Storage Technology Corporation, and is now only a historical footnote—as are nearly all the other Minnesotan firms.

In the first chapters, Misa brilliantly situates Minnesota in the geography of the computing industry. But he never addresses the reasons that the regional computing industry could not reinvent itself. Were the local industrial leaders too focused on the mainframe and competition with IBM and therefore unable to see the changes underway in the computing industry? Was it because of a lack of complementary assets? Was it that industry there could draw only on the University of Minnesota, while Silicon Valley and Boston had access to more (and more prominent) local universities? Or was it due to a shortage of venture capital, as Minnesota had only a few local firms, whereas Silicon Valley and Boston had nurtured far more vibrant venture capital industries? The question of how and why the assets dissipated is not addressed, leaving me wishing for more.

Nonetheless, Digital State is engagingly written and exhaustively researched. Those interested in the history of the computing industry will find it a welcome addition to their libraries.