Original Tarzan Novels
1. Tarzan of the Apes (1914)
2. The Return of Tarzan (1915)
3. The Beasts of Tarzan (1916)
4. The Son of Tarzan (1917)
5. Tarzan and the Jewels of Opar (1918)
6. Jungle Tales of Tarzan (1919) - A collection of short stories
7. Tarzan the Untamed (1920)
8. Tarzan the Terrible (1921)
9. Tarzan and the Golden Lion (1923)
10. Tarzan and the Ant Men (1924)
11. Tarzan, Lord of the Jungle (1928)
12. Tarzan and the Lost Empire (1929)
13. Tarzan at the Earth's Core (1929)
14. Tarzan the Invincible (1931)
15. Tarzan Triumphant (1932)
16. Tarzan and the Leopard Men (1932)
17. Tarzan and the City of Gold (1935)
18. Tarzan and the Lion Man (1936)
19. Tarzan and the Forbidden City (1938)
20. Tarzan's Quest (1939)
21. Tarzan and the Leopard Woman (1946) - Written after Burroughs' death by his wife, but it was completed from his notes and considered canon.
22. Tarzan and the Madman (1964) - Written after Burroughs' death by his wife, using notes, and considered canon.
Other Books featuring Tarzan
* Tarzan the Magnificent (1939) - A book by Burroughs featuring Tarzan, but it's part of a series featuring a different protagonist, the "Caspak" series.
* The Apes of the Jungle (1933) - Not a full novel, but a collection of Tarzan stories published in magazines prior to the novel "Tarzan the Invincible."
Note: There are many other Tarzan books written by other authors after Burroughs' death. These are not considered canon, but they may be of interest to some readers.
It's important to remember that the original Tarzan novels are considered the most faithful to Burroughs' vision of the character. The later books may have some inconsistencies with the original stories.