Brief Answers to the Big Questions revisits topics that author Stephen Hawking addresses in his first and most famous book for the general public, 1988’s A Brief History of Time. That work describes in simple terms what scientists have learned about the origin and unfolding of the universe. The book discusses how everything began, how the mysterious regions called black holes work, how atoms behave under the theory of quantum mechanics, and how time shapes reality. A Brief History of Time broke sales records: It appeared on England’s Sunday Times bestseller list for more than four unbroken years. The book has sold 25 million copies; a 2009 edition contains updates on the science it discusses.

Brief Answers tackles similar material but uses a question-and-answer format. The author made several of the discoveries mentioned in both books, and he developed a possible “theory of everything” that melds together two of the most fundamental underpinnings of physics: relativity and quantum mechanics. Hawking’s contributions to the development of physics, astrophysics, and cosmology are second only to Einstein’s work in their importance to advancing scientific knowledge and theory in the 20th century.