Justin Galland Schiller (born September 10, 1943) is an American bookseller specializing in rare and collectible children's books; proprietor during his student days under his own name (1960-1969), then Justin G. Schiller, Ltd. (1969–2020). Headquartered in New York City, it was the oldest specialist firm in the United States, focusing on historical and collectible children's books, related original art, and manuscripts. In 1988, he formed a second corporation—Battledore Ltd, with his partner and spouse Dennis M V David, to further specialize in original children's book illustration art and the legacy of Maurice Sendak.