This book delivers what it promises: engaging 100 thought experiments that are a wonderful introduction to the most basic philosophical puzzles. It is a great read for anyone new to philosophy and those who feel overwhelmed by the history of philosophy and keep asking themselves, "Well, where do I start?"
I, being someone who knew about half of the things discussed in this book, did not feel that it's boring or stale since the author cleverly wrote out different hypothetical scenarios as an introduction to each concept, and they were almost always humorous and witty (I mean, come on, the title IS a reference from a Hitchhiker's Guide book). Easily one of the best "popular philosophy" books.

It should be pointed out, however, that this is not a reference book; and that is why it doesn't leave you satisfied since it covers ideas VERY briefly and not in depth at all. Nevertheless, the author mentions the source of most experiments so you may easily expand on a particular subject (which is why I am at the moment waiting to get my copy of Thus Spoke Zarathustra!) Also, it cannot be read in one sitting: you read so little, and you think so much. Which makes this book a great one for those who are easily bored by reading walls of text, but don't mind spending too much time with it.

Overall, I recommend it. It's a nice addition to any library.