it created many variations in its high-quality toys, most of which were main characters or occasional guest stars in the Spawn series. But few, in the glut of new series, possessed lasting artistic quality and the items that were predicted to be valuable did not become so, often because of huge print runs that made them commonplace. The speculator market began to collapse in summer 1993 after Turok #1 (sold without cover enhancements) badly underperformed and Superman's return in Adventures of Superman #500 sold less than his death in Superman #75, something speculators and retailers had not expected. Companies began expecting a contraction and Marvel UK's sales director, Lou Marks, stated in September 29 that retailers were saying there was "simply no room to display all the comics being produced". The resulting crash devastated the industry: sales plummeted, hundreds of retail stores closed and many publishers downsized. Marvel made an ill-judged decision during the crash to buy Heroes World Distribution to use as its own exclusive distributor, which resulted in both distribution problems for Marvel and the industry's other major publishers making exclusive distribution deals with other companies, which would lead to Diamond Comic Distributors Inc. becoming the only distributor of note in North America. In 1996, Marvel Comics, the largest company in the industry and hugely profitable just three years before, declared bankruptcy. The crash also marked the relative downfall of the large franchises, inter-connected "families" of titles that lead to a glut of merchandising. While the big franchise titles still have a large amount of regular titles and merchandising attached to them, all of these things were notably scaled back after the crash. Rise of the trade paperback format Although sales of individual comic periodicals dropped in the late 1990s and the early 2000s, sales rose for trade paperbacks, collected editions in which several issues are bound together with a spine and often sold in bookstores as well as comic shops. Comic book publishers began releasing trade paperbacks of collected story arcs directly after those stories' original periodical publication, because a new reader could purchase the trade paperbacks and access the entire series' stories to date. The Librarian's Guide to Graphic Novels for Children and Tweens by David S. Serchay explains: "At first it was the most popular stories that were being collected, but more and more comic book stories are now being put into trade, sometimes less