- A Comparative Grammar of the Dravidian or South-Indian Family of Languages (1856; 2nd ed., 1875) (transcription project)
- Lectures on the Tinnevelly Missions (1857) (external scan)
- A Political and General History of the District of Tinnevelly in the Presidency of Madras from the Earliest Period to Its Cession to the English Government in A.D. 1801 (1881) (external scan)
Works about CaldwellEdit
- "Caldwell, Robert," in Dictionary of National Biography, 1901 supplement, London: Smith, Elder, & Co. (1901) in 3 vols.
- "Caldwell, Right Rev. Robert," in Dictionary of Indian Biography (p. 67), by C. E. Buckland, London: Swan Sonnenschein (1906)
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.