100 Under 100: The Race to Save the World's Rarest Living ThingsHarper360 Canada This book is a fascinating glimpse of Earths biodiversity, a call to action and an inspiring look at the efforts to save the rarest of rare. Scientists estimate that the total biodiversity on Earth is between 10 million and 100 million species. Of these, just over 1. 6 million and counting have actually been catalogued and described. One percent, or 16,306, of those species are threatened with extinction, about one fifth of them