British mathematician and astronomer Sir Fred Hoyle (1915-2001) coined the phrase 'Big Bang Theory' to describe the currently accepted explanation of the origin of the universe, and he did important work on the origins of stars and on the elements within stars. To the general public he was known more as a prolific writer of popular science books, in which he offered his stimulating ideas on the nature of our huge, fascinating cosmos. In this compilation of popular lectures delivered in 1964, he comments on the nature of the scientific enterprise, gives his view of life on Earth from the perspective of astronomy, and speculates about the future. Among the many interesting ideas discussed in this book is Hoyle's suggestion that 'the emergence of intelligent life is not a meaningless accident' and he estimates that the existence of intelligent life on other planets is highly probable. Despite the enormous distances that separate the stars and planetary systems, he considers it very likely that humanity will eventually discover the technological means to communicate with intelligent extraterrestrial life. He also feels that the developmental pattern of life on Earth is probably not unique and that we 'are following an inevitable path, one that must have been followed many, many times on other planets'. In conclusion, he conjectures that contact with more advanced civilisations may prove vital to learning how to address the most daunting problems of life on Earth, such as avoiding nuclear war and managing the global stresses of the population explosion. These forward-looking lectures by one of the 20th century's great scientific minds make for exciting and rewarding reading.