This book is designed as a textbook and is intended to present a sample of the more popular approaches to linguistic theorizing. It covers different aspects of each theory including general ontology, methodology, world view, and certain specifics including its problem-solving capacity regarding the English auxiliary complex. It gives a brief summary of the salient points of each theory and concludes with a brief treatment of concurrent developments in phonology. Included are discussions on: tagmemics, generative transformational grammar, stratificational linguistics, Montague grammar, generalized phrase structure grammar, lexical-functional grammar, relational grammar and functional approaches to grammar.