In the mid-20th century the R. R. Bowker Company published a slew of bibliographical tools and resources -- some of which had existed for decades before the advent of the paperback and many of which continue to this day -- that highlighted the paperback as a publishing phenomenon and which today help the retrospective researcher amass knowledge about the paperback books in publication and the publishing world's opinions about them.
What follows are Bowker bibliographic publications that either provide information about the paperback world of the 1940s-1980s or allow an assiduous researcher to track and reproduce the catalogs of the various series published by both trade and paperback houses of the time. Many are housed only in research university libraries today and infrequently available on the used market. Electronic availability, such as it is, is noted where applicable.
Books in Print (annual, 1948-)
Originally served as a Series-Title-Author index to PTLA and relied on PTLA for its information until the 1970s when it extended beyond the publishers' catalogs in PTLA. Database access through ProQuest today: http://www.booksinprint.com.
American Book Publishing Record (monthly, 1960-; annual, 1965-; various cumulations)
Fairly complete record of books published in America. Annotations are drawn from the weekly lists in Publishers Weekly but arranged by subject according to the Dewey Decimal System. Publications are also indexed by author and title.
Forthcoming Books (1966-)
Books in Series (4 eds., 1977-1985)
Series were extracted from the Library of Congress's National Union Catalog and MARC files, Bowker's Books in Print and Out-of-Print files, PTLA series listings, publisher materials, the ABPR database, and Irregular Series and Annuals.