try this : Frogs into Princes: Neuro Linguistic Programming
This book, which is the first official book on NLP, was definetly a hallmark in the changing of my thought process on psychotherapy, and psychology. Although quite basic NLP is presented, "Frogs Into Princes" is a book that must be read at least once a year, just like some other NLP books such as "Using Your Brain", "Change Your Mind","Trance-Formations", and "Reframing" just to list a few. It must be read once a year not due to any possible negative consequence upon the reader, but rather for the surprises and excitement of "missed" information, and "looked over" concepts that has not jumped out of the page to said owner. This is first book I have read on NLP and I highly recommend it especially as a beginning book on NLP. It is humorous, has a fresh style, and is quite informative. Eventhough some of the information presented in "Frogs Into Princes" is basic, they are building blocks for more advanced NLP techniques. This book, as well as NLP as a whole, as well as the other previously mentioned classics, I believe are underrated and underappreciated by the psychological and psychiatric community.

I have read and reviewed Adam Khoo's E-book Master Your Mind and I highly recommend it. Not for the faint of heart, it is 364 pages containing not only Adam's personal story of success but also the NLP applications and exercises. If you stick to it, it could be a life changer for you. Although, I also recommend his videos, the E-book is only $20 and well worth the investment if you actually put into practice what Adam teaches.

As an NLP Practitioner, I can testify to the power of this particular method of therapy and change management. It has also had a massive impact on my personal life and has led to opportunities that didn't exist before I became licensed.

I would say that all the books available may not make complete sense without some formal training as they use lots of jargon that is a bit 'insider' and might be tricky to grasp unless you have a better understanding of the subject.

If you do consider formal training, I think it is important to choose a provider with a decent pedigree and one that will ultimately lead to certification that is recognised by Richard Bandler. There are many programs that are not officially authorised by Bandler and co. and these should be avoided.

Beware of products that say they can teach you NLP as a way to manipulate or persuade people against their will for obvious reasons. Although NLP can give you tools of conversational hypnosis and persuasion, etc. to use these skills for malice or personal gain is highly unethical, in my opinion.

As a therapist I consider both clinical hypnosis and NLP to be very valuable tools in my therapy toolbox, tools I can honestly say that are in constant use. However, whilst hypnosis is often tagged as the easiest of therapies to learn but the hardest to master, NLP can be hard to both learn and master. This is in part because of the heavy NLP use of jargon and what I consider to be intentional over complication and elaboration. If you enjoy the technical and method based side of therapy and personal development then NLP will suit you, if you have a more holistic approach then NLP could challenge your methodologies.