"Endless forms most beautiful and most wonderful have been, and are being, evolved," Darwin famously concluded The Origin of Species, and for confirmation we look to...the guinea pig? How this curious creature and others as humble (and as fast-breeding) have helped unlock the mystery of inheritance is the unlikely story Jim Endersby tells in this book.

Biology today promises everything from better foods or cures for common diseases to the alarming prospect of redesigning life itself. Looking at the organisms that have made all this possible gives us a new way of understanding...