Author:George John Douglas Campbell
- The Reign of Law (1866)
- Primeval Man (1869)
- The Eastern Question (1879)
- The Unity of Nature (1884)
- Scotland As It Was and As It Is (1887)
- The Unseen Foundations of Society (1893)
- Philosophy of Belief (1896)
- Organic Evolution Cross-examined (1898)
- Autobiography and Memoirs (1906)
Articles in Popular Science MonthlyEdit
Works about CampbellEdit
- "Campbell, George Douglas, Duke of Argyll," in Alumni Oxonienses: the Members of the University of Oxford, 1715-1886, by Joseph Foster, London: Parker and Co. (1888–1892) in 4 vols.
- "Argyll, George John Douglas Campbell, 8th Duke of," in A Short Biographical Dictionary of English Literature, by John William Cousin, London: J. M. Dent & Sons (1910)
- "Argyle, George Douglas Campbell," in The New Student's Reference Work, Chicago: F.E. Compton and Co. (1914)
- "Campbell, George Douglas," in Dictionary of National Biography, 1901 supplement, London: Smith, Elder, & Co. (1901) in 3 vols.
- "Argyll, George Douglas Campbell, eighth Duke of," in Dictionary of Indian Biography (p. 17), by C. E. Buckland, London: Swan Sonnenschein (1906)
- "Argyll (Duke of), George Douglas Campbell," in Men of the Time (eleventh edition), by Thompson Cooper, London: George Routledge and Sons (1884)
Some or all works by this author were published before January 1, 1928, and are in the public domain worldwide because the author died at least 100 years ago. Translations or editions published later may be copyrighted. Posthumous works may be copyrighted based on how long they have been published in certain countries and areas.