Can nature make us happy? How can we know anything? What is justice? Why is there evil in the world? What is the source of truth? Is it possible for God not to exist? Can we really believe what we see? There are questions that have intrigued the world's great thinkers over the ages, which still touch a chord in all of us today. They are questions that can teach us about the way we live, work, relate to each other and see the world. Here Leszek Kolakowski explores the essence of these ideas, introducing figures from Socrates to Thomas Aquinas, Descartes to Nietzsche, and concentrating on one single important philosophical question from each of them. Whether reflecting on good and evil, truth and beauty, faith and the soul, or free will and consciousness, Leszek Kolakowski shows that these timeless ideas remain at the very core of our existence.