Speaking of old books on computer design... I've got a copy of "Logical design of digital computers" by Montgomery Phister, Jr. circa 1958, sitting right next to me. You know it's got to be legit if the word "digital", and "computer" are strung in the title.
Personally, I like the Noam Nisan and Shimon Schocken book "The Elements of Computing Systems" Published by MIT Press (so you know it's good stuff!) that I won at Toor Con on the panel with Captain Crunch. Good times.
Anyhow. I'd say, got to go with the 4-Bit system that is shown in the Radio Shack "Digital Electronics" book!