These legendary lectures from Richard Feynman, delivered in 1960 and recorded for the BBC, are the perfect example of his gift for making complex subjects accessible and hugely entertaining. Here, he gives his own unique, freewheeling take on the puzzles and problems that lie at the heart of physical theory, with lectures on Newton's Law of Gravitation, on mathematics as the supreme language of nature, on the mind-boggling question of whether time can ever go backwards, and on the exciting search for new scientific laws. They all use everyday illustrations to bring out the essence of a complicated principle - for example, his unforgettable analogy between the law of conservation of energy and the problem of drying yourself with wet towels. These lectures are a brilliant example of Feynman's mind in action, and sum up the essential scientific quest.