Around 1967 Charley accepted one last major commission from Western Publishing - illustrating Gerald Fichter's The Animal Kingdom.1
The 105-page book, a middle-school level introduction to zoology, allowed Charley to concentrate his efforts solely on animals. His hundreds of gouache paintings covered everything from single-celled organisms to insects to reptiles to fish to mammals. Pretty much, as the title would imply, the entire animal kingdom. It was in many ways an even more ambitious project than the Golden Book of Biology.
To support Fichter's text, Charley illustrated, among other things, sharks vs. stingrays, or squids vs. whales, or tarantulas vs. hummingbirds - exactly the stuff that would appeal to a pre-teen target audience. Charley's minimalist point-of-view on the brutality of the wild was nothing short of masterful and the result was a now hard-to-find classic.
Although Charley would continue with limited commercial freelance work throughout the 1970s and 80s, notably for the Ford Times, the Sohioan, Ranger Rick, and Procter and Gamble's Moonbeams, he would never again accept another commission on the scale of The Animal Kingdom.
Charley had spent 20 years as a freelancer creating a body of work so vast that a catalogue raisonné is simply impossible to compile and, now approaching 50 years old, it was clear that he needed to slow down. Perhaps more importantly, by this time much of his commercial illustration, especially his book-length nature work, was rapidly being replaced by photography. Charley and Edie's response was to reinvent themselves by returning to their artistic roots - the serigraph. It was precisely at this time they met the revolutionary Wood Hannah.
1. Fichter, George. The Animal Kingdom - An Introduction to the Major Groups of Animals. New York: Golden Press, 1968. The book went through at least (and maybe only) two printings and is available with two covers, one with black text and one with red text.