This book is a companion to the 1991 Granada TV series "James Randi: Psychic Investigator" (although you don't need to have seen the programme to enjoy the book) and discusses the experiments shown in the programme and any relevant off-screen information (such as participants agreeing to take part and then dropping out at the last minute, participants who stated that they were happy with the procedure before the tests took place but then claimed it had all been biased when they didn't demonstrate the abilities they claimed to have etc.). There's also a lot of general information about paranormal abilities.
James Randi is a pretty high-profile sceptic and, as a result, tends to attract a lot of criticism. I bought this book to find out for myself a little more about him, and I was impressed with his emphasis on unbiased testing in the book. He makes a very valid point that it should be possible to replicate any supernatural abilities under scientific, controlled conditions, and, despite what his critics would have you believe, he seems to take every possible step to ensure that the participants are happy with the design of the experiments (they can request any changes they feel necessary) and believe they can demonstrate their abilities under those conditions. On the only occasion when a participant actually managed to demonstrate his professed abilities, Randi very generously suggests that the participant may indeed have supernatural abilities, despite the participant accidentally having access to key information regarding the experiment.
The book's a tad on the short side, but if you're interested in finding out more about James Randi and his experiments, I would highly recommend this book.