The first part consists of heavily edited versions of von Neumann's famous 1949 lectures given at the University of Illinois. Burks' commentary is interesting though I would like to see the complete lectures.

The second part is a construction of the text von Neumann was working on at the time of his death. This is heavy reading because it's the foundational work of a new field. If one's interest is playing around with CAs there are probably more accessible options.

The book design unfortunately has the figures and schematics for the CA appended instead of intermingled.