I would also suggest anyone that is interested in BEAM robotics to take a look at Braitenberg Vehicles[1]. These are simple reflex-based robots that can exhibit complex behaviors due to their interaction with their environment. Originally, they were thought experiments by the psychologist Valentino Braitenberg who showed in his book, Vehicles[2], how one might ascribe complex emotional and mental states to a simple automaton if one only observed its external behavior. For a fascinating earlier example of analog robotics, (and the first example of true autonomous robotics to my knowledge) one has the work of Grey Walter and his "tortoise" robots[3].

[1] https://en.wikipedia.org/wiki/Braitenberg_vehicle

[2] https://books.google.com/books?id=7KkUAT_q_sQC (there appears to be excerpts available for free as pdfs)

[3] https://en.wikipedia.org/wiki/William_Grey_Walter