This is a book about the human brain, the people of which it is a part, human behaviours and linguistic abilities, and the evolution of these characteristics. The author has spent his academic life-time in the study of language and its evolution, and this book reflects his deep passion for this subject. The book is written in a very conversational manner, drawing on the author's observations, as well as on the hard science that he has been central to the development of. This makes it both readable and infuriating, with its asides and changing themes, sometimes enlightening, sometimes distracting. The central theme of the book is human unpredictability, although the nature of this trait as described here might be described alternatively as creativity, or the ability to innovate or improvise. It is the brain that makes humans creative and innovative, and indeed, unpredictable. The brain is usually compared to the most complicated machine of the day, giving it privilege as the most difficult-to-understand organ of the body, regardless of whether those studying it live in the present-day, or in Victorian England. Philip Lieberman presents an up-to-the-moment account of this organ in evolutionary frame, pulling together evidence from a very diverse range of disciplines, as well as personal experience. The chapters in the book variously consider: brain architecture and neuroscience; the brain in learning and language; natural selection and the evolution of cognition; the evolutionary development of the human brain; archeological evidence of human creativity; why language, according to the author, is not innate; and the biological bases of human unpredictability. Within these chapters he argues against some of the most popular and influential thinkers of the moment in human evolution and linguistics, Richard Dawkins, Stephen Pinker and Naom Chomsky among them. In the case of these three individuals, he takes a key idea of theirs and argues for its lack of universality. While this is put forward by the author as at least partial falsification, the choice of evidence is eclectic and far from scientific. Lieberman is much more solidly grounded when he talks about the brain, its evolution and about language; in this he presents a very readable account in the first half of the book. Does he explain unpredictability? No, largely because the term is not defined nor formulated in a way that would allow rigorous examination. The idea of creativity, often used interchangeably with that of unpredictability, is also framed in too broad-ranging a way for precise scrutiny.

Despite these criticisms, this is an important book. It tries to engage with the vague, imprecise matters that many of us consider the hall-mark of humanity: the myriad ways in which humans can play, invent, build, subvert, network, initiate and respond, often on a moment-by-moment basis. Such creativity is fundamental to our evolutionary and ecological success as a species, at least thus far. Lieberman is right to point out that human evolution, and the cultural and behavioural diversity that present-day humans have, is a work in progress. And that the discourse described in his book is a starting point. Lieberman is at an age and stage in his life when he can take on the popular scientific giants of the moment with relative impunity. I praise him whole-heartedly for doing so, and recommend this book to anyone with an interest in what we are as a species.