Concealing-Coloration in the Animal Kingdom: An Exposition of the Laws of Disguise Through Color and Pattern; Being a Summary of Abbott H. Thayer’s Discoveries is a book published ostensibly by Gerald H. Thayer in 1909, and revised in 1918, but in fact a collaboration with and completion of his father Abbott Handerson Thayer's major work. The book introduced the concepts of disruptive coloration to break up an object's outlines, of masquerade, as when a butterfly mimics a leaf, and especially of countershading, where an animal's tones make it appear flat by concealing its self-shadowing.