While I cannot say that I have had the priviledge of working on one of these pieces of machinery, I think any geek will be humored by some "How Computers Work" books written in the '70s. Scanned images of the books reveal the inner workings of the computer, explaining all aspects of the inner- and outer-workings of the computer. A fun trip back in time to see how far we've come and appreciate what the pioneers of computing went through to bring this new tool to modern society.