The Apollo Guidance Computer
Frank O'Brien
I really enjoyed this book. There is plenty of detail, interesting facts and a great story. I personally might have like to see a few more code samples but this is a story of some very clever people doing something far in advance of what the technology was initially capable of.
We learn about the development of the hardware, robust enough (physically and electrically) to survive in the harsh space environment. I particularly liked the neat idea of add a shift operation when your command addressing space is already full - just arrange for a particular memory location to implement a one-bit right shift on the data written. Read it back and you have your shift operation!
And then on top of that we get the clever programs, the well thought out user interace and the interaction with physical instruments and ground computers. In effect there is also an early “virtual machine” implementation here as well.
Great stuff for space technology nerds!