It's a good little introduction ... inspite of the errors and inaccuracies another reviewer mentioned.
The book focuses more on explaining what some of the jargon and terms mean rather than explanations of how a derivative is structured and traded.
I'd say the book will let you understand what people say about derivatives, and how they fit into the bigger picture, as oppose to understanding derivatives themselves. I don't suppose there is a catchy title in there though!
A helpful read for a newcomer, but leaves one wanting more. I don't feel ready to tackle one of those weighty tomes explaining derivatives in full ... we need someone to recommend an intermediate book!