Like us, aliens would be constrained by the physical world. The physical demands on life and intelligence impose amazingly narrow restrictions on all aspects of intelligent life.

Originally published in Great Britain by Profile Books Ltd, 2016.

How alien would aliens be? Would they look like us or perhaps more like an octopus? How would they communicate? Could we even hear their voices, assuming they have them? Like us, aliens would be constrained by the physical world. Understanding how those physical constraints apply both to us and to aliens is the theme of this book. The constraints imply that they will not be all that different from us, perhaps half to twice as big as we are. They will depend on vision and hearing as we do and they will live on a planet much like ours. But where will they be? Do they even exist? The odds are not good. We may be the only intelligent life in the universe.

DISCOVER HOW LIFE REALLY WORKS - ON EARTH AND IN SPACE 'A wonderfully insightful sidelong look at Earthly biology' Richard Dawkins 'Crawls with curious facts' Sunday Times _________________________ We are unprepared for the greatest discovery of modern science. Scientists are confident that there is alien life across the universe yet we have not moved beyond our perception of 'aliens' as Hollywood stereotypes. The time has come to abandon our fixation on alien monsters and place our expectations on solid scientific footing. Using his own expert understanding of life on Earth and Darwin's theory of evolution - which applies throughout the universe - Cambridge zoologist Dr Arik Kershenbaum explains what alien life must be like. This is the story of how life really works, on Earth and in space. _________________________ 'An entertaining, eye-opening and, above all, a hopeful view of what - or who - might be out there in the cosmos' Philip Ball, author of Nature's Patterns 'A fascinating insight into the deepest of questions: what might an alien actually look like' Lewis Dartnell, author of Origins 'If you don't want to be surprised by extraterrestrial life, look no further than this lively overview of the laws of evolution that have produced life on earth' Frans de Waal, author of Mama's Last Hug

A thoughtful, clear and utterly fascinating reference, this book is absolutely vital to writers who want to put extraterrestrial life-forms in their novels and stories.

The inspiration for the Netflix series 3 Body Problem! Over 1 million copies of the Three-Body Problem series sold in North America PRAISE FOR THE THREE-BODY PROBLEM SERIES: “A mind-bending epic.”—The New York Times • “War of the Worlds for the 21st century.”—The Wall Street Journal • “Fascinating.”—TIME • “Extraordinary.”—The New Yorker • “Wildly imaginative.”—Barack Obama • “Provocative.”—Slate • “A breakthrough book.”—George R. R. Martin • “Impossible to put down.”—GQ • “Absolutely mind-unfolding.”—NPR • “You should be reading Liu Cixin.”—The Washington Post The Dark Forest is the second novel in the groundbreaking, Hugo Award-winning series from China's most beloved science fiction author, Cixin Liu. In The Dark Forest, Earth is reeling from the revelation of a coming alien invasion-in just four centuries' time. The aliens' human collaborators may have been defeated, but the presence of the sophons, the subatomic particles that allow Trisolaris instant access to all human information, means that Earth's defense plans are totally exposed to the enemy. Only the human mind remains a secret. This is the motivation for the Wallfacer Project, a daring plan that grants four men enormous resources to design secret strategies, hidden through deceit and misdirection from Earth and Trisolaris alike. Three of the Wallfacers are influential statesmen and scientists, but the fourth is a total unknown. Luo Ji, an unambitious Chinese astronomer and sociologist, is baffled by his new status. All he knows is that he's the one Wallfacer that Trisolaris wants dead. The Three-Body Problem Series The Three-Body Problem The Dark Forest Death's End Other Books by Cixin Liu Ball Lightning Supernova Era To Hold Up the Sky The Wandering Earth A View from the Stars At the Publisher's request, this title is being sold without Digital Rights Management Software (DRM) applied.