You have a choice in reading this book; take a senior course in evolutionary biology, or spend an hour carefully reviewing the introductory glossary. Don't be intimidated by this initial labour, however, there are great rewards awaiting you for the effort.
Our present view of life's parade is unaccountably dominated by the parade of dinosaurs encountered in cartoons, advertising and poorly conceived cinema. Conway Morris brings to view the truly important period in evolution's pageant. Fossils of the Cambrian era were hidden from view until the 1909 discovery of a city-block-sized outcrop in the mountains of British Columbia. The Burgess Shale revealed fossils of a plethora of hitherto unknown soft- bodied creatures. Conway Morris recalls this find, and expands this initial discovery with other sites around the globe to give us a more intimate view of the creatures inhabiting that time.
Reference to Stephen Gould's WONDERFUL LIFE is almost mandatory here. Conway Morris doesn't 'disparage' him, but shows that Gould's excited imagination and desire to support his invalid thesis of 'punctuated equilibrium' led him into fallacious assumptions. Conway Morris has brought hard science to point out the realities of the Cambrian record. Evolution's mechanics have been addressed from several angles. Conway Morris reviews these, offering sound critiques to each in developing his thesis. What caused the 'Cambrian explosion' of novel life forms? Predation. Animals that had scuffled along the sea bottom or waited for food to drift into reach were challenged by more ambitious life forms. Conway Morris has given us an engaging account of the development of life.
There are few flaws in this account. It's amazingly complete for so brief a treatment. Conway Morris barely wastes a word [except an excruciating repetition of the phrase 'this remains controversial'] in his account. He covers the fossils, their form of life, and how these creatures led to the life forms we encounter today. This is not a 'specialist' book, but worth a purchase by anyone wishing to grasp the role of evolution in our lives.