This is a very short book from Feynman (~120 pages of actual text) and comprises of the transcripts of 3 lectures he gave in April 1963. They are as far removed from his technical lectures as can be imagined, so are easily accessible to the lay reader. The impression I got was that these lectures are Feynman trying to find his own mind, by talking out loud and seeing where the train of thought goes. In fact he admits that he covers all the key ground he wants to in the first two lectures, and these are noticeably more coherent than the last one, which takes up nearly half the book.
He covers various topics, though the key themes are uncertainty and the limits of science. He does touch on some potentially incendiary ground such as religion and politics, though he always measured and reasonable, never resorting to polemicism or off-handed dismissal. There is some evidence of the threat presented by the Cold War in the lectures.
Feynman's virtue as a scientist is present throughout, as he is quick to put down the “argument from authority” though he doesn't quite name it as such. Probably of most interest to the modern reader is the interaction between science and religion. Here, Feynman takes a very reasonable and fair-minded approach, more akin to Stephen Jay Gould than the ranting polemic of Richard Dawkins. He is also quite firm in the belief that scientific methodology cannot rule on morality; that is, there are subjective things in this world that are beyond the reach of science.
At times, he does get close to waffling a little bit, and the fact the book is taken verbatim from his lectures means that he interrupts himself on more than a few occasions. The book certainly provides food for thought, and I would recommend it to anyone interested in the place of science in society. It is probably not the best introduction to Feynman and his work (for that, I would recommend Surely You're Joking, Mr Feynman) though for those familiar with this other work, this will be a valued addition to your RPF library.