Was Perry Mason in a book before he was on the television?

Yes,

Perry Mason first featured in a novel published in 1933 - The Case of the Velvet Claws by Erle Stanley Gardner. He went on to feature in over 80 novels and short stories.

He also appeared on radio from 1943 to 1955 and in two series of television programmes 1957 to 1966 and 1973 - 1974, and in a series of made-for-television films from 1985 to 1993.