and selling comic books has greatly increased the visibility of actual comic book sale prices, leading to improved price guide accuracy, particularly for online price guides such as comicspriceguide.com and GPAnalysis. GPA only tracks sales of slabbed books, and therefore is not an accurate indicator of overall comic sales. In response to collectors' interest in preserving their collections, products designed for the protection and storage of comic books became available, including special bags; boxes; and acid-free "backing boards", designed to keep the comic book flat. History Origins Before the late 1960s, virtually no specialized comic stores existed and the notion of comics as collectible art was in its infancy. A few collector-based retail establishments existed, most notably Pop Hollinger's retail and mail order shop for new and used comics in Concordia, Kansas, which was in full swing by 1940. Claude Held had followed suit in Buffalo, New York, by 1946. The origins of comic book collecting as an organized hobby has its roots in early science fiction fandom and comic book letters pages. In the early 1960s, DC Comics began publishing the full addresses of the people writing in, which allowed comic fans to reach out to each other. In the US a few specialist shops had opened their doors by the 1960s, but were still a small market. In the UK, the only distribution channels available were ordinary news stands and mail order publications like Exchange and Mart or through zines run by the early panelologists themselves. Denver, Colorado-based retailer Chuck Rozanski played a large role in the growth of the comics speculation market in 1977 when he acquired the high-value "Mile High Collection" — 16,000 comic books dating from 1937 to 1955 — and slowly began releasing select books into the marketplace. During the late 1970s–early 1980s major comic publishers like Marvel and DC Comics started to recognize the new movements and started publishing material that was intended for sale in specialist shops only. When Marvel tested the new comics specialty market with the title Dazzler in 1981, the comic sold over 400,000 copies, a very respectable figure and one that astounded the company. Hereafter, comics publishers started tailoring ever-increasing percentages of marketing and production solely for the sale in specialist stores. While the bulk of the revenues still came from sales through regular channels, the ability to focus more specifically on specific target groups as well as