This book comprehensively updates the Meta-model. It is widely recognised as the sequel to THE STUCTURE OF MAGIC VOLUME I, by Richard Bandler. It contains all the new extensions to the Meta-model discovered since that book was published in 1975. The original thirteen language distinctions have now been increased to twenty-two in the most comprehensive study of the language used in human communication ever produced. Crown House Publishing
This is definitely a useful book. To call it the sequel to the Structure of Magic seems a bit much to me, but the additional ideas brought in from Korzybski are definitely useful additions to the standard metamodel distinctions.