The Merge Hypothesis is the central empirical theoretical contribution of the Minimalist Program (MP) to syntactic theory. This book offers an accessible overview of the MP, debunking common sixty years of Generative research, culminating in GB theory. He introduces The Fundamental Principle of Grammar, which advocates including labels as part of the Merge Operation and centring the notion of the constituent as the key domain of syntactic commerce. The early chapters identify the goals of the MP, how they arose from earlier descriptive and explanatory successes of the mentalist tradition within Generative Grammar, and how to develop them in future work to expand its descriptive and explanatory range. It is essential reading for anyone interested in contemporary syntactic theory.