One of my favorite primary sources for the Computer Boys book was the Programmer’s Coloring Book. In fact, I recently used a cartoon from that series for a forthcoming article in Information & Culture that I wrote about the history of the software flowchart.
It is only recently, however, that I learned about the larger popularity of adult coloring books (no, not that kind of “adult”…). in the 1960s. Laura Marsh at the New Republic has a brilliant new article on The Radical History of 1960s Adult Coloring Books (in which she references this site). I wish that I had been aware of this a few years ago!