This book is a collection of refereed invited papers on the history of computing from the 1940s to the 1990s with one paper going back to look at Italian calculating/computing machines from the first century to the 20th century. The 22 papers cover a wide range of computing related topics such as specific early computer systems, their construction, their use and their users, software programming and operating systems, people involved in the theory, design and use of these computers, computer education, and conservation of computing technology.