Micro-organisms are of fundamental importance in soil development and productivity, and therefore, in turn, of prime significance for agriculture and human health. This book gives an account of the important processes that are driven by microbial activity in soil, and is an updated translation of the book originally published in German. It is clearly written, albeit with a rather abrupt or note-like style (perhaps a consequence of the translation), but this makes presentation of key facts and statements very clear. The book opens with a survey of soil properties and methods for microbe quantification, with two chapters then detailing aerobic and anaerobic organic matter decomposition, with emphasis on plant materials. N, S and P turnover in soil is then outlined, followed again by a chapter on organic matter decomposition in relation to composting, and methane production. This is followed by an account of trace gases in soil, especially nitrogenous gases and methane, and finally a chapter on heavy metals as pollutants, together with a brief account of toxicity, environmental aspects and microbial resistance. The text includes a good number of figures and tables, which clearly relate to the text, and there is an ample bibliography, which could lead readers to more detailed accounts of the topics discussed. Clearly the topic is huge, and the authors have succeeded in greatly simplifying and reducing to the most important points in this short volume. The book is of value to undergraduate and postgraduate students, or indeed other readers new to the field.