This book features advice, the science of happiness, and brief accounts of real people reaping the rewards of following these practices (or suffering the consequences if they do not).
It is neither a boring, dry, technical textbook of psychology, nor is it a bouncy, meaningless, 'slogans and nonsense' typical self-help book.
Instead, it is a very readable mix of scientific findings with a healthy dose of advice and examples.
It is laid out with 100 separate entries, and can be read straight through or referred to now and again as way to pick yourself up or redirect your thoughts and efforts.
If you are thinking about reading a book on this topic, I think this is the one that you will find the most useful.