ABC-CLIO/Greenwood is an educational and academic publisher (middle school through university level) which is today part of ABC-CLIO. Established in 1967 as Greenwood Press, Inc. and based in Westport, Connecticut, Greenwood Publishing Group publishes reference works under its Greenwood Press imprint, and scholarly, professional, and general interest books under its related imprint, Praeger Publishers. Also part of GPG is Libraries Unlimited, which publishes professional works for librarians and teachers. 

The company was founded as Greenwood Press, Inc. in 1967 by Harold Mason, a librarian and antiquarian bookseller, and Harold Schwartz who had a background in trade publishing. The company initially focused on reprinting out-of-print works, particularly titles listed in the American Library Association's first edition of "Books for College Libraries" (1967), under the Greenwood Press imprint, and out-of-print periodicals published as "American Radical Periodicals" under the Greenwood Reprint imprint. In 1969 the company was sold to Williamhouse-Regency, a company then on the American Stock Exchange, which led to further expanding its reprint activities as well as starting a microform publishing imprint, Greenwood Microforms. 

By 1970 a small scholarly monograph program was established and Robert Hagelstein, formerly with the Johnson Reprint Corporation, a division of Academic Press, was hired as Vice President. In 1973, Mason and Schwartz left the company, and Hagelstein was named President, a position he would hold until his retirement at the end of 1999. During those twenty-seven years, the press wound down its reprint activities diverting its focus to new scholarly, reference, and professional books. This large-scale redirection of the company resulted in the publication of more than 10,000 titles during those years.
When did they sell it?
In 1969 the company was sold to Williamhouse-Regency,