Out of interest, who do you regard as the founders of CS theory - I'd probably go for Church and Turing, but I can see arguments for others as well.
The other surprising thing to me was that it didn't really resemble modern algebra at all. As a former math student I think it's easy to create a mental model of math history where when new fields are created they resemble the modern incarnation. But when you actually look at the primary founding texts its clear the ideas and notation are pretty unrefined at least compared to today's standards.
I've just started reading it and Petzold claims all you need is a decent grasp of high school mathematics.
Glad to see I'm not the only one...