A Jamaican-born poet and novelist, Dallas's fictional works included Percival, or Nature Vindicated (1801), Aubrey (1804), The Morelands. Tales Illustrative of the Simple and Surprising (1805), The Knights: Tales Illustrative of the Marvellous (1808), and Sir Francis Darrell; Or the Vortex (1820). He also published a volume of poems, two dramas, and some polemical works. He had a connection for some years with Byron, and his Recollections of the Life of Lord Byron from the year 1808 to the end of 1814 (1825) was published posthumously. He also authored The History of the Maroons from their Origin to the Establishment of their Chief Tribe at Sierra Leone (1803).