The Marvelous Illusion studies four works by composer Morton Feldman dating from 1970-71. Focusing on the listener's attention to sounds themselves, Feldman created the "marvelous illusion" of sounds shaping into coherent music through the act of perceiving them, rather than through the act of composing. Each work appears to assemble itself for the listener as they experience it. Author Thomas DeLio frames these analyses with a discussion of Feldman's relationships to important contemporaries in other arts, revealing that above all Morton Feldman's music is about sound and spontaneity, connections arising for the listener as the composition is heard.