Book review The spinning magnet: the force that created the modern world – and could destroy it, by Alanna Mitchell, London, Oneworld Publications, 2018, 323 pp., RRP US$28.00, ISBN: 978-1101985168 The subject of this new book is the Earth’s magnetic field, with special reference to the reversals of the poles and their consequences. It is told in a very engaging and sometimes informal way. In the author’s own words, “What you are about to read is a translation of some ideas from science into journalism”. Alanna Mitchell is an acclaimed science journalist, having won prizes and awards for her work, and, in October 2018, Mitchell was guest speaker at one of the monthly meetings of KEGS, the Canadian Exploration Geophysical Society. Previous reviewers have said that this book is “a spellbinding scientific detective story”, gives “explanations of complex physics in easily understandable terms”, and “Mitchell puts magnetism on the map!”. My assessment is that the book is a diverting introduction to the subject, and a pleasant review for those who know the traditional history and are keen to know the latest (there are references to publications up to 2017). This book is not a textbook in the standard sense, as it is without diagrams or equations, although it has a good index and bibliography. To this end, the story is not always told in a logical sequence or without distractions. In this regard, it is instructive to compare it with a more academic study on the same subject, “North Pole South Pole” written by Gillian Turner, a scientist specialising in the subject. However, Turner’s book is current only to 2010.1 Apart from a Preface, which explains how the author became interested in the subject, the book has four parts: Magnet, Current, Core and Switch. The first two parts deal with the discovery of magnetism, and its association with electricity as a classical physics subject. They include the standard protagonists from Pliny the Elder to Maxwell, including Gilbert, Faraday and many others. Once introduced, most of these individuals reappear in later chapters as if old friends. While the standard theoretical story of the Earth’s magnetic field can easily be found on the web (for example, https://, to the reader familiar with the subject it is the more recent developments, and the researchers that Mitchell has got to know, that are of interest. These appear in Parts 3 and 4, Part 3 dealing more specifically with the internal geophysics of the geodynamo, and Part 4 dealing with solar activity and its effects of a possible diminishing of the field’s strength, if not its cessation. The chapters in each part (totalling 10, 7, 8 & 6 respectively) are, with only one exception, fewer than 10 pages in length. Perhaps this is to make for an easy read. The chapter titles are often seemingly obscure, and not easily relatable to their subject. One called“Pharaohs, fairies, and a tar-paper shack”, refers to Mitchell’s way of referring to“ferros”and“ferris”types of magnetism. This book has the most annoying way of providing endnotes. Instead of superscript numbers in the text, which would apparently detract from 1 North Pole South Pole was reviewed by Ted Lilley in Preview, Oct 2010. 30 PREVIEW Book review FEBRUARY 2019