From the Editor´s Desk

This issue features several articles that discuss different perspectives on innovating computer technology. Specifically, the issue includes features on the emergence of computer engineering in the United States from the mid-1940s to the mid-1950s; the history of a large Swedish producer of mechanical calculators, Facit; a history of Chaim Selig Slonimski and his adding device inventions in the late 1800s; and the development of the programming language CPL in the early 1960s. It also include an article that applies a methodological approach to the historiography of computing and suggests using the concept of "information hiding" to distinguish the kinds of information that get hidden when human beings interact with different types of computing machines.