Peter Max, one of the most visible and successful artists of his generation, died Monday in Manhattan at 88. His son, Adam Max, confirmed the death at a hospital; he had long suffered from dementia.

Max's trippy posters of Day-Glo flowers, butterflies, rainbows, stars and planets sold by the millions and expressed the blissed-out exuberance of the countercultural 1960s. A vegetarian and teetotaler who expanded his consciousness through yoga, not drugs, he became fabulously wealthy from licensing his paintings and posters.

Through half a dozen businesses bearing his name, he entered licensing agreements with more than 70 companies. His simple graphic images lent themselves to products from sheets and glassware to airplanes and a Postal Service stamp. Incorporating Art Nouveau, Op Art and psychedelic motifs, his designs offered instant visual gratification and a cheery endorsement of love, joy and universal consciousness.

Born in Berlin in 1937, he moved with his family to Shanghai, then Haifa, and in 1953 to New York, settling in Bensonhurst, Brooklyn. He studied at the Art Students League and began his career designing an LP sleeve for Riverside Records in 1962.