Before the Internet, books used to have an order form that one could mail in with check or money order or credit card for other titles in the series on the last page of every single copy of every single title in the series. I have only seen this in books, why did board game companies never enclose a miniature catalog of other games in the series with an order form or toy companies who would say on the original package "Collect them all!" with valid pictures of the other toys in the series never enclose an order form in the original box? Why did only book publishers do that (as far as I know)?