"Endless Forms Most Beautiful - The New Science of Evo Devo and the Making of the Animal Kingdom" by Sean B. Carroll

First published: 2006
350 pages (paperback)

Evo Devo stands for 'Evolutionary Developmental Biology' and is an emerging field that combines insights from animal development with evolutionary theory.
The book first explains the genetic mechanisms by which complex multicellular organisms could evolve from simple unicellular ones and then goes on to show how "tinkering" with those basic mechanisms could lead to the diversity we now observe in nature.
Carroll himself is an accomplished veteran in the field of fruit fly development and therefore can provide first hand examples from the organism that was first used to elucidate the mechanisms and genes behind animal development. One main insight was that the genes responsible for controlling developmental processes have been conserved across the entire animal kingdom, including the human branch. Another important revelation was that it's not really the genes themselves that make the difference but more the patterns in which genes are turned on and off during development by so-called genetic switches. The examples given in this book of how these switches work include the formation of limbs as well as the formation of such patterns as the stripes of zebras and the spots on butterflies. The book comes with lots of colour figures to illustrate the beauty of animal forms.