Self-help gurus and business coaches preach the same simple mantra: if you want to improve your life, you need to change how you think. Force yourself to have positive thoughts, and you will become happier. Visualize your dream self, and you will enjoy increased success. Think like a millionaire, and you will magically grow rich.

In principle, this idea sounds perfectly reasonable. However, in practice, the approach often proves surprisingly ineffective, with research showing that people struggle to continually think happy thoughts, that employees remain unmoved by imagining their perfect selves, and that those dreaming of endless wealth fail to make millions.

Over a century ago, the brilliant Victorian philosopher William James proposed a radically different approach to change. Since then, researchers from across the world have carried out hundreds of experiments into James’s theory and discovered that it applies to almost every aspect of people’s lives. Perhaps most important of all, the work has given rise to a series of easy and effective exercises that can help people feel happier, avoid anxiety and worry, fall in love and live happily ever after, stay slim, increase their willpower and confidence, and even slow the effects of aging.

This research has been presented at countless scientific conferences and published in academic journals, but it has rarely made its way into the public domain.

The As If Principle presents the first accessible and comprehensive guide to James’s radical theory. It reveals how everything you currently believe about your mind is wrong, shows that change does not have to be challenging, and describes a series of easy-to-implement techniques designed to improve several different areas of your everyday life.

Throughout the book you are going to be presented with interactive exercises that involve you changing your behaviour. You might be tempted to read about these ideas but not actually put them into practise. This attitude is perhaps understandable (after all, behaviours quickly become ingrained in our minds and soon start to feel like old friends), but please resist the urge. This book is all about the impact that your actions have on your mind, and the exercises encourage you to actually experience these phenomena rather than just read about them.

You are about to encounter a new approach to change. An approach that is grounded in science, overturns conventional thinking, and provides a basis for the easiest, quickest and most effective ways of changing your life.

Forget all about positive thinking. It's time for positive action.