Stan and Jan Berenstain were already successful cartoonists for magazines and adult humor books when they began writing children's books. The first story starring the bear family, The Big Honey Hunt, appeared in 1962. Since then, more than 250 Berenstain Bears books have been published, and more than 260 million copies have been sold. What began as an idea sparked by their young sons' interest in children's books has become over the years arguably the best-selling children's book series ever.