Here is a list of all the Xanth books currently available.

1. A Spell for Chameleon (1977)
2. The Source of Magic (1979)
3. Castle Roogna (1979)
4. Centaur Aisle (1982)
5. Ogre, Ogre (1982)
6. Night Mare (1983)
7. Dragon on a Pedestal (1983)
8. Crewel Lye (1984)
9. Golem in the Gears (1986)
10. Vale of the Vole (1987)
11. Heaven Cent (1988)
12. Man from Mundania (1989)
13. Isle of View (1990)
14. Quesiton Quest (1991)
15. Color of her Panties (1992)
16. Demons Don't Dream (1993)
17. Harpy Time (1994)
18. Geis of the Gargoyle (1995)
19. Roc and Hard Place (1995)
20. Yon Ill Wind (1996)
21. Faun and Games (1997)
22. Zombie Lover (1998)
23. Xone of Contention (1999)
24. The Dastard (2000)
25. Swell Foop (2001)
26. Up in a Heaval (2002)
27. Cube Route (2003)
28. Currant Events (2004)
29. Pet Peeve (2005)
30. Stork Naked (2006)
31. Air Apparent (2007)
32. Two to the Fifth (2008)
33. Jumper Cable (2009)
34. Know Gneiss (2010)
35. Well-Tempered Clavicle (2011)
36. Luck of the Draw (2013)
37. Esrever Doom (2104)
38. Board Stiff (2014)
39. Five Portraits (2014)
40. Isis Orb (TBD)