I thought this book is quite sensible compared to most other self-help books out there. It doesn't shamelessly promote the ideas within the book, it just tells you what has been shown to probably work in positive psychology, and what hasn't, and introduces some ideas the reader can try as well. It's very easy to understand and apply its techniques. I also found some interesting resources on CBT from the links provided. It's simplicity might also turn out to be a weakness if you like details and going really deep into something, but for a general overview it's good, and it has more than enough stuff for you to try yourself.