The London publishing firm George Routledge and Sons, which had been revived by a group of investors in 1902, took over the management of Kegan Paul, Trench, Trubner in 1911. The firms were separately managed until 1947, when they merged as Routledge and Kegan Paul. The company flourished with the publication of academic and text books, largely in the social sciences, and from 1958 issued titles in paperback. It opened an American office in the 1970s, and an office in Australia in 1980. In 1983 it launched the Pandora imprint, dealing with women's issues.
In April 1985 Routledge and Kegan Paul was taken over by Associate Book Publishers (ABP), a publishing conglomorate attempting to achieve economic efficiencies by merging various publishing houses and facilities. ABP sold Routledge to the Thompson Publishing Group in 1986. From 1998 Routledge was part of the Taylor & Francis Group, where it continued as a leading imprint for books and journals in the social sciences and humanities.