A Briefer History of Time

March 1, 1988
Hawking's discovery that black holes emit particles caused great excitement among astronomers. In this succinct overview of current theories of the cosmos, the Cambridge University physicist modestly weaves in his own notable contributions while giving due credit to his colleagues. He explains why relativity implies that a "big bang'' occurred and examines string theory, which posits a universe of 10 or 26 dimensions. His understanding of time's flow leads him to conclude that intelligent beings can only exist during the expansion phase of our increasingly chaotic universe. New research on black holes and subatomic particles holds implications for scientists who, like Hawking, are attempting to devise a unified theory linking Einstein to quantum mechanics. The merit of this book is Hawking's ability to make these ideas graspable by the lay reader.

Starred review from September 26, 2005
In the 17 years since the publication of A Brief History of Time, Dr. Hawking's bestselling exposition of physics, new data from particle physics and observational astronomy have shed light on efforts to find a Grand Unified Theory of Everything that Hawking and Mlodinow use to enhance and update their answers to basic questions about the universe: where it's going and how it began. Discussed at length are the mysterious dark matter and dark energy-both of which can only be observed by their gravitational effects and are believed to make up 90 percent of the universe. Another area of research that has exploded in the past 20 years is string theory. Hawking and Mlodinow provide one of the most lucid discussions of this complex topic ever written for a general audience. Readers will come away with an excellent understanding of the apparent contradictions and conundrums at the forefront of contemporary physics. Recognizing that much of their audience will also be science fiction buffs, they include a chapter on the possibility of time travel. "Don't bet on it," the authors advise. Throughout these discussions, the authors maintain the same wry, lively tone that made the original Brief History such a delight. They close with a discussion of where physics ends and philosophy begins, "Why does the universe exist at all?" They cannot provide the answer, but they do provide an immense amount of food for thought. Highly recommended.