For anyone who suspects they ought to start thinking about their financial future, but also suspects, sensibly, that it's incredibly hard to work out who to trust, this is a fantastic book. It's really accessible and won't talk down to you. It's very evident that the authors have experience of helping ordinary people (I.e. not the rich) face real problems. Can't recommend it highly enough.
Some people will find, after working through this book, that they want to go even further and delve into the philosophy of investment. In that case I would also recommend John Kay's "the long and the short of it" and free on the Internet, Buffett's letters to shareholders.