1. Adventures and Experiences of a Sportsman on the West Coast of Africa (1868)
2. Savage Africa: Being the Narrative of a Tour in Equatorial, Southwestern, and Northwestern Africa (1864)
3. The African Sketch-book (1873)
4. The Origin of the Aryans (1890)
5. Play and Politics (1892)
6. Historic Studies in Vaud, Berne, and Savoy, from Roman to Medieval Times (1905)
7. Annals of Innocence and Experience: A Child's Reminiscences (1910)
8. The Veil of Maya: A Romance (1912)
9. The Life of Christ: A Study (1914)
10. The Valley of the Kings: A Historical Romance (1916)
11. The Martyrdom of Man (1924)
12. The Metaphysics of Nature: A Study in the Development of Speculative Thought (1926)
13. The Kingdom of God: A Discussion Between Men of Faith and Agnostics (1928)
14. The Last Crusade (1929)
15. Nature's Finer Forces (1931)
16. The Story of the Bible: A New Interpretation (1932)
17. What Really Happened at Calvary? (1933)
18. The New Morality (1934)
19. Heaven and Hell (1935)
20. The Immortality of the Soul: A Study in Human Experience (1936)
21. God's Candle: A Story of the Nativity (1937)
22. The Way to Eternal Life (1938)
23. The End of the World (1939)
24. The Mystery of Life: A Study in Biology and Psychology (1940)