Lynn Margulis (1938-2011) was a Professor of Geosciences at the University of Massachusetts, a member of the U.S. National Academy of Sciences and the Russian Academy of Natural Sciences.
This isn't really the edition I have. Mine doesn't say "Diversity of life" or "Issues in focus." I just says "third edition."
This book gives a equal-treatment description of every phylum on Earth, giving as much attention to the prokaryots and protists as to the animals, plants and fungi. (It was written before Archaea were widely recognized.)
Sound dull? Well, I wouldn't read this book straight through either. But there are odder practices among the single-celled residents of our planet than have ever been proposed by the most imaginative writer of fantasy, science fiction, romance, or erotica.