Seeing is believing

At the very start of this impressive book, Nicholas Wade's opening chapter takes readers on a whirlwind tour of the early history of optical illusions. Wade notes that written accounts of optical oddities date back to antiquity, with Ptolemy (ad 100–170) providing an early classification of illusions into those concerned with colour, position, shape, size and movement. Fast-forward almost two thousand years, and the same type of organisational framework forms the backbone of this current compendium. The book is divided into 11 parts (including colour, faces, grouping, motion, and so on), with each part containing a series of essays reflecting different aspects of the general theme. All of the 115 essays are richly illustrated (including, of course, many, many illusions), and the glossy format of the book easily accommodates the colour images needed to bring many of the illusions alive. In addition, the authors have helpfully provided a companion website, and this allows readers to experience those illusions requiring video-based stimuli.

The range of illusions covered is breathtaking, and one would be hard-pressed to find a more complete picture of the current research into visual illusions. At one moment readers find themselves learning about individual differences and the perception of illusions, whilst a few pages later they discover the nuts and bolts of the Ames Window. The essays have been written by leading academics, and the writing feels both accessible and authoritative. The brevity of the essays means that the book would act as a wonderful introduction to the study of optical illusions. However, the depth and range of the writings means that even the most experienced of researchers will find something new and surprising here. All of the essays are well referenced, and so provide a useful gateway into additional work. This book will not just inform and delight psychologists, but will also fascinate anyone interested in perception, including artists and designers.

In terms of potential criticisms, it might have been nice if some of the authors had focused more on the discovery of some of the illusions, in part, because such stories often provide a fascinating glimpse into the serendipitous nature of science (such as when a member of Richard Gregory's laboratory rediscovered the Münsterberg illusion in the tiled wall of a Bristol café). Also, it might have been good to have some of the essays reflect more on what has yet to be discovered within their specific domain (thus providing a useful resource for those wishing to conduct future research), and perhaps on the way in which some of the illusions have been used to tackle problems outside of the laboratory.

However, these are very minor gripes. Overall, this is a remarkable achievement. It presents an astonishing account of a vast amount of work, and deserves a place on the shelf of anyone interested in the current state of research into optical illusions. Like most illusions, this book has to be seen to be believed.

- Reviewed by Professor Richard Wiseman, University of Hertfordshire.