:59 Seconds by Professor Richard Wiseman

A thoroughly entertaining book about self help with a scientific perspective that attempts to answer the challenge of providing you with real techniques that you can understand in less than a minute to make yourself happier.

Not only that, reading the book manages to make you feel happier, it is light and positive with just the right element of challenge. Like having some helpful older relative offering you some decent advice.

There is an exercise towards the start that takes a while to complete, but it is definitely worth working through, and does not require a major investment of time and energy.