This book is a collection of papers dealing with the philosophical, conceptual, and empirical foundations of phonology, its position and relation with respect to syntax and phonetics in the theory of language, and the nature and acquisition of phonological knowledge. The introductory chapter by the editors provides a comprehensive discussion of the main themes presented in the following 11 chapters, in which diverse perspectives are represented. Bromberger and Halle open with a discussion of phonology within the context of the philosophy of language. Some chapters take a highly formal view of phonology: Hale and Reiss argue that phonology operates without reference to phonetic substance, and van der Hulst maintains that phonology and syntax are subject to the same operating principles. In contrast, the chapters by Burton-Roberts and Carr argue that phonology is substantive and should be excluded from the language faculty. Some papers adopt a more empirical approach: Docherty and Foulkes argue that phonological knowledge must include systematic sociophonetic variation; Fitzpatrick and Wheeldon discuss psycholinguistic research on spoken word comprehension; and Pierrehumbert, Beckman, and Ladd advocate experimental verification of phonological theory. Issues related to phonetics versus phonology are addressed by Myers, who distinguishes the gradual versus categorical nature of phonetics and phonology, Harris and Lindsey, who propose that vowel features are formulated on the basis of phonetic spectral patterns, and Vihman and Velleman, who discuss how phonological categories emerge from phonetic input in child language acquisition.