To be used for what in particular?
So I was a hypnotherapist before med school and psych residency.
Common uses are for anxiety d/o's including PTSD, phobias, habit changes (like smoking).
The first thing to recognize is that many texts are old and written by individuals experienced in hypnosis, not in necessarily in medicine or in complex mental illnesses.
Some basics include Hypnotherapy by Dave Elman; The Application of Ideomotor Techniques (by Dr. David Cheeks, an Ob/Gyn, currently out of print); Essentials of Clinical Hypnosis, a manual on the basics of hypnosis published by the Amer Psychological Assoc.
Let me know if you're looking for anything more particular or advanced.