This book is the second edition of an overview of the mites (Acari), which explores their fascinating biology, with emphasis on ecology, evolution and behaviour. The Acari are small arthropods (usually 0.2–0.5 mm in length, except for the larger ticks) that live, as the subtitle states, ‘‘at a microscale’’, in all habitats where life is possible. These include the soil and plants, invertebrates and vertebrates (including humans), in fresh and salt waters, even down to 7.000 m in the oceans, on mountain tops and the Antarctic. As the authors write, having read over 1.600 scientific publications, the ubiquitous mites are major components of biological diversity. Following a few general chapters on the origins of mites, a systematic survey of the Acari and of their life cycles, the authors discuss sex (including ‘‘Why Have Sex?’’) and celibacy. This is followed by longer chapters on mites in the soil, in fresh and salt water, on plants (including pests) and those that affect animals and may cause or transmit diseases. The book concludes with two chapters of more general interest, about mite biodiversity and on the Acari as models; each chapter ends with a clear and concise Summary. The authors use their extensive experience with soil and plant mites (DEW), and with water and bird mites along with acarine reproduction (HCP) to thoroughly and expertly explore these topics. The authors’ own experience and observations, especially in the eastern Australian rain forests, are smoothly integrated into the text, as are DEW’s personal adventure with mites (p. 438). They make the valid point that many of today’s students may be well trained in subcellular processes and genomics, but not in studying living organisms. The authors, however, are well versed in all these areas, as becomes clear throughout the text. An important feature of this book is the authors’ ability, by their mega-look at the literature, to indicate lacunae of knowledge about mite biology and thus to suggest the testing of relevant hypotheses (e.g. the costs and benefits of sex, p. 466). Furthermore, they also point at topics where research has sadly lagged, including the neglect of studies on soil biology (p. 211), or the non-use of water mites in water quality assessments (p. 272).