This is not an exhaustive list, but these are a few code history books I really like. These are books that focus a bit more on technical characters, as opposed to business leaders, and they're all good reads. Some are better than others, but I really liked all of these for different reasons.
Some are more distant history, and a couple are more contemporary accounts.
If I had to pick, I would recommend The Innovators as the first to read from the list because it covers a lot of ground, and Isaacson is a great writer. However, I'd say these can be read in any order. I'll edit this list if I think of any I missed. Feel free to add any more goodies to the comments.