NY: Viking, 1978. First US edition. Illustrated. SIGNED by William Burroughs and by Brion Gysin on the half-title page. An important exposition of Burroughs and Gysin's cut-up and fold-in techniques of assemblage, tape recorder experiments and film, and a treatise on the process of collaboration: "The third mind is the unseen collaborator, the superior mind constructed when two minds are put together." Near Fine in Near Fine dw. (white title lettering and edges of flaps partially tanned).