<P> U.S. paperbacks quickly entered the Canadian market . Canadian mass - market paperback initiatives in the 1940s included White Circle Books, a subsidiary of Collins (U.K.); it was fairly successful but was soon outstripped by the success of Harlequin which began in 1949 and, after a few years of publishing undistinguished novels, focused on the romance genre and became one of the world's largest publishers . </P> <P> McClelland and Stewart entered the Canadian mass - market book trade in the early 1960s, with its "Canadian best seller library" series, at a time when Canadian literary culture was beginning to be popularized, and a call for a Canadian author identity was discussed by the Canadian people . </P> <P> A mass - market paperback is a small, usually non-illustrated, inexpensive bookbinding format . This includes the U.K. A-format books of 110 mm × 178 mm (4.3 in × 7.0 in) and the U.S. "pocketbook" format books of a similar size . These are generally printed on low quality paper, which discolors and disintegrates over a period of decades . They are commonly released after the hardback edition and often sold in non-traditional bookselling locations such as airports, drugstores, and supermarkets, as well as in traditional bookstores . </P> <P> In 1982, romance novels accounted for at least 25% of all paperback sales . In 2013, 51% of paperback sales were romance . Many titles, especially in genre fiction, have their first editions in paperback and never receive a hardcover printing . This is particularly true of first novels by new authors . </P>

How big is a mass market paperback book
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