Integrating the results of comparative morphology, experiments on pattern development, the genetics of color patterns, and theoretical modeling of pattern formation, Nijhout shows that the enormous diversity of natural patterns arises largely from quantitative variations in a small set of readily understandable generating rules.
Thomas C Emmel describes this book as "...the most direct, comprehensive, and integrated exploration of development in morphological evolution in any group of organisms." As such it goes into quite a lot of the scientific detail relating to the genetic and developmental mechanisms, building on (and modifying) the basic insight (from research carried out in the 1920s) of 'The Nymphalid Ground Plan', so you do really need to have some prior interest in these areas. The painstaking aggregation of experimental detail in this book bears testament to an impressive level of sustained scientific patience and commitment in the unravelling of the mechanisms behind the diversity of wing patterns found in the Lepidoptera. What is most wonderful about this treatise though is that you come away from it with a renewed sense of awe - because the mechanisms at work interact in such a dynamic interactive fashion that the resultant patterns are shaped by the environment (into mind-blowing mimicries, camouflages, and dazzling displays etc), contain traces of their own morphological development and still leave room for the intricate accidents of chance.