cover image The Great Extinctions

The Great Extinctions

Norman MacLeod. Firefly Books, ($29.95) ISBN 978-1-77085-187-0

MacLeod takes readers on an interesting 500 million year excursion through the history of life and death on Earth. The first five chapters provide definitions, context, and historical perspective for the current understanding of stratigraphy, the fossil record, and the classification of life within an evolutionary framework. The book concisely offers insight into the limits of knowledge within these fields, and these insights give non-experts some basis to evaluate competing opinions. Macleod also provides a window into the to-and-fro of the scientific process where theories can migrate from the lunatic fringe to scientific orthodoxy as new observations come to light. MacLeod analyses eight extinction events beginning in the Precambrian Eon and working towards the near past. Each chapter follows a format that allows readers to compare key elements from each event. Scientific terminology from the geological timescale and biological classification can be daunting but excellent graphs, pictures, and diagrams help to clarify and enliven difficult subject matter. Overall, it is a good introduction to the great puzzle that is extinction study, impressive in its presentation of the scope of work already done and tantalizing to the curious with countless mysteries still unsolved. (Feb.)