Fourth printing has inside front cover indicia which says 'Printed by Apex Novelties and published by the San Francisco Comic Book Company', same as the first and third printings. The back cover art is printed at 6 1/4" wide, separating it from the first printing which is printed at 5 1/2" wide. Fourth printing is differentiated from the third printing by front cover has '1970' missing after Crumb's signature.