Dr Lass examines certain crucial issues in phonological and general linguistic theory through detailed studies of English phonetics, dialectology and language-history. He argues that contemporary 'standard' phonological theory is inhibited and misled by the related disadvantages of an artificially constrained formalism and a restricted database. He confronts theories of English phonology with a much wider range of material than is usual, drawing for example on Scots, Northern and North-Midland English, East Coast American dialects, and many others. Dr Lass offers solutions to many outstanding problems in the history of English. All the detailed discussions are informed by an overriding concern for the methodological and philosophical issues suggested by such problems. What kind of discipline is linguistics? What kinds of knowledge do its procedures yield and how are they validated?