Maurice Sendak’s 80th year — which ended with his birthday earlier this summer and is being celebrated on Monday night with a benefit at the 92nd Street Y — was a tough one. He has been gripped by grief since the death of his longtime partner; a recent triple-bypass has temporarily left him too weak to work or take long walks with his dog; and he is plagued by Norman Rockwell.

Or, to be more accurate, he is plagued by the question that has repeatedly been asked about Norman Rockwell: was he a great artist or a mere illustrator?

“Mere illustrator,” he said, repeating the phrase with contempt. It’s not that Mr. Sendak, who has illustrated more than 100 books, including many he wrote, is angry that people question Rockwell’s talent; rather, he fears he has not risen above the “mere illustrator” label himself.

Never mind that Mr. Sendak’s originality and emotional honesty have changed the shape of children’s literature; that his work is featured in museums; that he has designed costumes and sets for operas, ballets and theater; that he has won a chest full of awards and prizes including a National Medal of the Arts. As the playwright Tony Kushner, one of his collaborators, said, “He’s one of the most important, if not the most important, writers and artists ever to work in children’s literature. In fact, he’s a significant writer and artist in literature. Period.”