Textbooks are undergoing an evolution. First, there was the single-author textbook, which was usually held to be definitive or, at least, authoritative. This was replaced more recently by edited textbooks, for which experts wrote chapters on their areas of specific interest. This book — the third in the World Psychiatric Association's series ‘Evidence and Experience in Psychiatry’ — is an example of the next stage in this evolution. The format involves a series of reviews on topics within dementia, each review followed by commentaries. The reviews focus on: definition and epidemiology; clinical diagnosis; neuropsychological and instrumental diagnosis; pharmacological treatments; psychosocial interventions; and the costs of dementia.

Although the book purports to be evidence-based, it does not quite get there. For example, the reviews, although on the whole well written and fairly comprehensive, are not systematic. There is no attempt to identify all available published and unpublished evidence or to quality-filter the evidence identified, and no attempt to synthesise the results into a meta-analysis. As they stand the reviews therefore merely reflect the opinions of the authors.

The commentaries are similar in format to peer-review commentaries, and therein lies one of the strengths of this book. For example, the chapter on definition and epidemiology has 14 commentaries, each with a slightly different focus, and the commentary authors read like a Who's Who of Old Age Psychiatry. Each commentary is about two pages long and is followed by its own reference list.

The principal advantage of this way of arranging a textbook is that a vast number of experts are able to contribute. Unfortunately, however, many of the commentaries start with rather congenial commendations of the authors of the reviews, which is a bit wearisome after a while. Indeed, it seems that some authors of the commentaries are rather reticent about disagreeing with the reviews.

Is this book useful? Yes, it is. Although it falls between the two stools of the conventional textbook and systematic reviews, it is a great compendium of up-todate facts and opinions. However, there is too little application of evidence-based principles to call it an evidence-based textbook. It does take rather a long time to learn how to get around the book effectively, but it is helped by a good index, which includes the commentaries as well as the review articles.