Assemblage, Environments & Happenings is a founding document of performance and environmental art. Initially planned as an official Fluxus publication, it evolved into this broader book in which Kaprow explains the concept of Happenings—spontaneous, unscripted, often collaborative events that might include performance, sculpture, sound, and audience participation.
Artists covered include Robert Rauschenberg, Claes Oldenburg, Red Grooms, and George Segal, with contributions from Wolf Vostell, George Brecht, Kaprow and others.

First edition; (304 x 304 mm, 12 x 12 in); black-and-white photographs and illustrations, light staining to text block; black endpapers, brown burlap-covered boards, titles stamped in light brown on spine and upper side, publisher's fitted vinyl dust-jacket, lightly worn, shaken as usual, a very good copy; 344pp.