During the 1960s and 1970s, he was responsible for a great many album covers, and helped create the graphic style of that era. He designed a series of science fiction book covers for Penguin Books. He made a big impression with his illustrations for The Beatles Illustrated Lyrics book. He also provided illustrations for "The Penguin Book of Comics", a history of British and American comic art. His work was characterised by a flowing, cartoony style and soft airbrushing – very much in step with the psychedelic styles of the times. His work includes the 1971 anti-war poster entitled "A great place for hamburgers but who'd want to live there!"