its based on a real episode involving a popper lecture at cambridge, at the behest of russell, with W in the audience. whether W threatened popper with a poker (and what an interesting way to dispense with the old goat ;-) -- young goat at that time, probably!) etc is debatable, IIRC. i haven't read the book and do not plan to... W is an interesting and inspiring figure but i am afraid i would end up agreeing more with popper's philosophical positions.
jks, have you heard of the new tarski bio by the fefermans? cambridge says its not available till nov, but i see that amazon.com is selling it.
http://titles.cambridge.org/catalogue.asp?isbn=0521802407
i am no good at reading biographies, but its a feferman book and you (or others) may be interested!
--ravi