Your request for book recommendations is an often-asked question and it is difficult to answer accurately because no one really knows what you want the knowledge for.  So I have made some categories, which I hope will help. This list is by no means exhaustive and changes from time to time according to whim.

1.  NLP

Ok the classic text here is "Frogs into Princes"; most of the old classics by Grinder & Bandler as well as the old crowd of NLPers are fantastic. So "Reframing", "Using your brain for a change", "Heart of the Mind", "Sleight of Mouth", “NLP The New Technology of Achievement” “Magic of NLP Demystified”, etc are all great. The books that started it all were "Structure of Magic Vol 1 & 2", these are more academic reads but still well worth the read if you want to truly understand the heart of what makes NLP, or hypnosis work - the structure of people's thinking!

As a starter I'd recommend read "Frogs into Princes" and work you way into the others over time (especially after you have taken some NLP training), that’s how I began.

2.  Hypnosis

OK there are many more great books in this category than you can shake a stick at. So forgive me if I keep the list relatively brief (I could go way OTT on this!)

i. Trance Formations (Grinder & Bandler): this is still one of the best intro texts for hypnosis and language. It’s simple to read, elegant, and presents some very useful and powerful models of hypnosis.

ii. Therapeutic Trances (Stephen Gilligan): an absolute masterpiece of

Ericksonian hypnosis. Gilligan is the man that did a full deep trance ID with Erickson (wheelchair, paralysis & everything!) back in the 70s and it really shows in this masterful exposition of hypnosis. It’s a harder, more advanced read however.

iii. Training Trances (Overdurf & Silverthorn): This is another classic book in the "Trance Formation" vein. The whole book is written in hypnotic language and is a very elegant description of the foundational Ericksonian patterns of trance. Very nice double induction at the beginning using some very elegant phonological ambiguities.

iv. Monster's & Magical Sticks - There's No such Thing as Hypnosis? (Steven Heller): This is a great light read about hypnosis, again demonstrating Ericksonian hypnosis at work in many different situations. Its a lovely read and demonstrates some of the principles very elegantly. Not so much of a how to book.

v. Erickson's Published Papers CD-Rom (available from www.anglo-american.co.uk )

This is an absolute treasure, a bit pricey but worth it. These people have published on CD-Rom pretty much every paper that Erickson ever published, plus a few unpublished ones. There are some real gems to be gleaned from arguably the world's greatest master of hypnosis. This is NOT for beginners, as it can get very technical and at times requires some wading through, but persistence is rewarding!

vi. “Therapeutic Metaphor” by David Gordon. This book is in textbook style so it isn’t an especially easy read. But it does teach you how to craft a metaphor to have therapeutic results for a specific client. It will also give you insight to Virginia Satirs use of categories.

vii. “Hypnotic Suggestions and Metaphors by D. Corydon Hammond PhD. A very comprehensive book giving numerous varied methods of working with different client problems. For example there are over 20 different approaches to pain management. The chapter on forming hypnotic and post hypnotic suggestion is limited but very good with what it did include.  

viii. “Hypnotic Realities” Erickson and Rossi Awesome detailed dissection of Erickson doing trance work with explanation and commentary by both Erickson and Rossi as each suggestion is given.

ix. “Hypnotherapy” Erickson and Rossi Analysis of Erickson doing casework.

x. “The Practice of Hypnotism” Andre Weitzenhoffer  A very well done work on hypnosis and how to utilize it in the theraputic situation. Weitzenhoffer does a real good job of defining the three main differentiations of thought in hypnosis today, and then loses a lot of credibility by trying to discredit Ericksonian hypnosis, by only succeeding in demonstrating that he doesn’t understand Ericksonian hypnosis. Still that aside, Weitzenhoffer has put together a very worthwhile book that has plenty of good stuff to make the extravagant price tag worth while.

xi “Hope and  Resiliancy” Short, Erickson, Klein Written by two of Ericksons daughters and Short, this book goes a long way towards demystifying Ericksons methods. A must read.

Xii “The February Man” Rossi Takes one theraputic treatment (several sessions) and records it verbatim, then Erickson and Rossi discuss and analyze the complete therapeutic process by dissecting the sessions word for word.

The above is what I would recommend as a core library for any NLP/Hypnotist. There are thousands of other great texts however (e.g. Elman's "Hypnotherapy", Esdaille's "Mesmerism in India", Sidis' "The Psychology of Suggestion" and Most of Ernest Rossi's books on clinical subjects)

3.  Hypnotherapy

- see above

4.  Stage Hypnosis

There’s is really only one classic that tops them all in this category:

i. “The New Encyclopedia of Stage Hypnosis” (Ormond McGill): Includes pretty much everything you need to know about stage hypnosis from cover to cover (including a few sample shows!) It’s a great light read (though repetitive at times). Ormond is very much an "Old world" hypnotist into his mysticism and mesmerism - which is fine if you ascribe to that, and quaint if you do not. Much great advice is given on all aspects of a show, from understanding hypnosis, to understanding showmanship (NOT the same thing!) and even advertising you.

5.  Clinical Hypnosis

Its easier to recommend authors than actual books in this field, so here goes: Ernest Rossi, Jeff Zeig, Stephen Gilligan, Erickson, Michael Yapko, Jay Haley, Andre Weitzenhoffer, Erickson (usually co-authored with another person)

6.  Altered States of consciousness

i. Clark Hull's "Hypnosis and Suggestibility" is an old classic that details almost 1000 experiments in hypnosis. A great read, but NB Hull is the one that made the original mistake in the 30s which has plagued hypnosis ever since - he tried to pigeon hole trances by putting a standard induction on a record and then concluding that only 20% of people can go into a deep trance. Hogwash! 20% can only go into a deep trance using only that SPECIFIC method! So watch out for that mistake.

ii. ” Hypnotic Realities” Erickson, Rossi; is again a fascinating though slightly

Academic text.

iii. Mind Games (Masters & Houston): A great collection of hypnotic

adventures and explorations based on Ericksonian hypnosis.

iv. “Extreme Spirituality” (Tully Berkan): defined for me the path from belief, to certainty, to action. 

v. Holographic Universe (Michael Talbot): Wow, this book combines the theories of two premier researchers, one a physicist and the other a psychologist to form a coherent theory about reality and how we create it.

vi. Miracles of Mind” Russell Targ and Jane Katra PhD This is the most definitive book on the interconnectedness of the universe, what Jung called the collective unconscious. It also has the best references to double blind studies on ESP, PSI, and remote viewing. Explicit instructions on how to remote view yourself and how to enhance your ability. Fabulous discussion on time, and its properties and its relation to precognition. And then Jane takes up on energy healing. Absolute must read, and the references cited are a trail filled with gold nuggets!

vii "Prometheus Rising" Robert Anton Wilson" Without a doubt one of the best at teaching the difference between reality and belief and how belief shapes and creates your reality, both tangible and intangible. Each chapter has a couple of "exercises" so that you actually get to experience the things taught in that chapter. Don’t read this if you like your current illusion.

viii "The Hiram Key" Knight and Lomas. Take care with this book! By taking a historically accurate look at the origin of Christianity you are liable to have your faith in 'Christianity' severely tested, or your faith in any other religion for that matter.

ix. “A Short History of Nearly Everything”  Bill Bryson Excellent and entertaining synopsis of development and current scientific thought, from the ‘beginning’ of time to now. Excellent.

xx. A double “Blink” and “Tipping Point” by Malcom Gladwell Blink describes how fast the unconscious ‘learns’ and recognizes patterns. Great read for understanding, but stops short of exercises or what to do with the information. “Tipping Point” describes the way an idea ‘takes hold’ and ‘flourishes’, in the ‘people’ system.