Contains mail art contributions from a wide variety of artists including Woody Van Amen, Anna Banana, Robert Barry, Ben Vautier, Joseph Beuys, Stanley Brouwn, Hans Peter Feldmann, Robert Filliou, Ken Friedman, Sigurdur Gudmundsson, Allan Kaprow, Ko de Jonge, Ulay, Soll Lewitt, Raul Marroquin, Pieter Mol, Arnulf Rainer, Dieter Roth, Allen Ruppersberg, Edward Ruscha, Robert Smithson, Jiri Valoch, Edgardo Antonio Vigo, Wolf Vostell, Emmett Williams and others.