Since antiquity, i.e. for at least 2,500 years and probably much longer, people have been asking themselves what it means to live a good life. How should I live? What constitutes a good life? What's the role of fate? What's the role of money? Is leading a good life a question of mindset, or is it more about reaching your goals? Is it better to actively seek happiness or to avoid unhappiness? Each generation poses these questions anew, and somehow the answers are always fundamentally disappointing. Why? Because we're constantly searching for a single principle, a single tenet, a single rule. Yet this holy grail - a single, simple path - doesn't exist. Over the past few decades, a silent revolution has taken place within various fields of thought. Within science, politics, medicine and many other areas, scholars have come to realise that the world is far too complicated to summarise in one big idea or handful of principles. We need a toolkit of mental models in order to understand the world. It's high time somebody compiled a similar toolkit designed for practical living. Voila. Here you'll find fifty-two such intellectual tools - they may not guarantee you a good life, but they'll give you a better chance.