NLP stands for Neuro-Linguistic Programming.
It is the attempt to train, read, and manipulate cognitive patterns.
NLP uses perceptual, behavioral, and communication techniques to make it easier for people to change their thoughts and actions.
 

The concept is founded on the idea that people operate by internal “maps” of the world that they learn through sensory experiences.  NLP then tries to detect and modify the unconscious biases or limitations of an individual’s map of the world.
 

For the most part, this method of training was created by Richard Bandler and John Grinder in the 1970s. NLP methodology can "model" the skills of exceptional people, allowing anyone to acquire those skills.  The use of these skills has been adopted by hypnotherapists and also by companies that run seminars marketed as leadership training for businesses and government agencies.

By challenging linguistic distortions, specifying generalizations, and recovering deleted information in the client's statements, we can get a more complete representation of the underlying deep structure of our thoughts and have therapeutic benefit as we deal with these things and change them into more productive patterns.

Tony Robbins, who trained with Grinder utilizes ideas from NLP as part of his own self-help and motivational speaking programs, and has been very successful as both an author and a life Coach.