Forbes edited
Adam Ferguson's
An Essay on the History of Civil Society for the University of Edinburgh Press in 1966. In 1970 Pelican Books published the volumes of
David Hume's
History of Great Britain that covered the early Stuarts, to which Forbes wrote the introduction. In his book ''Hume's Philosophical Politics'', Forbes argued that Hume's main purpose in writing
The History of England was to give "the Hanoverian regime a proper intellectual foundation". Against the traditional portrayal of Hume as a Tory, Forbes labelled Hume's beliefs "skeptical Whiggism", that is, an acceptance of the
Revolution Settlement coupled with a rejection of most other Whig orthodoxies such as the concept of the "
ancient constitution". Forbes' work on the
Scottish Enlightenment led to one of his students,
John Dunn, calling him "a Highlander in exile". ==Works==