This is a fabulous work. Well written, almost a page turner. I've read, or been reading, Protein Evolution by Laszlo Patthy and Molecular Evolution by Page and Holmes. These are good books, but left me wanting clarification and greater depth. I searched the UCSD BioMed Library and discovered Li's Molecular Evolution. Just what I was looking for. It's a nice improvement over the Principles of Molecular Evolution by Li and Graur. I note a new edition of the latter book is due out soon which makes me wonder if the new book might not be an update to Li's book. The only reason I didn't give the book 5 stars is the typography. The print and style of the earlier work by Li and Graur is far superior.