I was introduced to his work thanks to a well-intentioned tongue-lashing by Baird Searles at the Science Fiction Shop on Eighth Avenue when I was a teenager ("You love New York and science fiction and you've never read 334????"). Even as I drifted away from the field, I would always snap up a book of his. He was one of the best writers in the field, and one of the few so-called new wave writers whose work remained consistently good as he got older.
He wasn't the friendliest guy, but when I met him at an SF convention at Columbia University sometime in the early 80s, he did sign my dealer-table paperback* copies of 334 and Camp Concentration with a smile and a friendly remark around his cigar.
*Baird Searles was the kind of bookseller who would talk enthusiastically about a book even to someone who obviously wouldn't be able to buy it (for instance, a kid who'd just had to put one book back, having done the sales-tax arithmetic wrong and therefore not having enough money to buy them all). I miss the Science Fiction Shop.