LONDON (AP) — Mal Peet, an irreverent, award-winning British writer of books for children and young adults, has died aged 67.

Peet's agent, Peter Cox, said the writer died Monday. He had been diagnosed with cancer several months ago.

Peet wrote young-adult novels, as well as educational children's books co-authored with his wife Elspeth Graham. He won the 2005 Carnegie Medal for "Tamar," a historical novel set during World War II.

His first novel for adults, "The Murdstone Trilogy," was published last year.

Cox said the world had lost "an author of exceptional genius."

"The Fault in Our Stars" author John Green tweeted that Peet was "one of the greatest YA writers and a man I greatly admired (even when we disagreed!)"

Peet is survived by his wife, three children and two grandchildren.