Why did Samuel Langhorne Clemens use pseudonyms? Does the “Autobiography of Mark Twain” mention his real name on its title page?

The question is not how Samuel Clemens chose Mark Twain as his pen name. The question is why he used any pen name at all, and why he used so many of them. 

The following list of his pen names was found online:

1. Mark Twain

2. Devil

3. Figaro

4. Fred Ballard

5. Grumbler

6. John Snooks

7. Josh

8. Moralist of the Main

9. Ramblr

10. S. Browne Jones

11. Sergeant Fathom

12. Soleather

13. Son of Adam

14. W. Epaminondas Adrastus Blab

15. W. Epamondas Adrastus Perkins

16. W.E.A.B

17. William Jones

18. Thomas Jefferson Snodgrass

Quintus Curius Snodgrass (discredited)

19. Carl Byng (possible)

In view of my recent posts, which relate the failure of an autobiography’s title page to mention the person’s real name to the person’s having multiple personality, I wonder whether the Autobiography of Mark Twain mentions Samuel Clemens on its title page.

[Note: Search "Mark Twain" to read a number of previous posts.]