Functional Categories and Parametric Variation is an attempt to make sense of the idea that functional categories are the "flesh and blood of grammar." From within the context of the Principles and Parameters framework put forward by Chomsky and others, Jamal Ouhalla develops the argument that much of what we understand by the term grammar involves functional categories. His main thesis is that most, if not all, of the information which determines the major grammatical processes and relations (movement, agreement, case, etc.) are associated with functional categories. Furthermore, these categories are also the major locus of information determining language variation. This has major implications for the overall structure of the language model. In identifying parameters with a set of lexical properties, this approach could be construed as an attempt to dispense with the notion of "parameter" altogether.

Although this book explains for the first time the role of functional categories and language variation from within a coherent and explicit Chomskian framework, Functional Categories and Parametric Variation is comprehensible to non-Chomskian linguists. It is an original and important contribution to syntactic theory.