Howard Rheingold published Tools for Thought back in 1984, which he has since put online. It comprises a concise and informative history of the computer, covering important figures of the last 200 years. If you would like to know what a computer is, where it came from, and where it may be headed, take a look.
Note: the above link is my local copy of the original. I've edited a few typographical errors, and made the local copy just in case the original disappears. The pages are copied from www.rheingold.com with permission.