A synchronic sociolinguistic study of Jamaican Creole (JC) as spoken in urban Kingston, this work uses variationist methods to closely investigate two key concepts of Atlantic Creole studies: the mesolect, and the creole continuum. One major concern is to describe how linguistic variation patterns with social influences. Is there a linguistic continuum? How does it correlate with social factors? The complex organization of an urbanizing Caribbean society and the highly variable nature of mesolectal speech norms and behavior present a challenge to sociolinguistic variation theory. The second chief aim is to elucidate the nature of mesolectal grammar. Creole studies have emphasized the structural integrity of basilectal varieties, leaving the status of intermediate mesolectal speech in doubt. How systematic is urban JC grammar? What patterns occur when basilectal creole constructions alternate with acrolectal English elements? Contextual constraints on choice of forms support a picture of the mesolect as a single grammar, variable yet internally-ordered, which has evolved a fine capacity to serve social functions. Drawing on a year's fieldwork in a mixed-class neighborhood of the capital city, the author (a speaker of JC) describes the speech community's history, demographics, and social geography, locating speakers in terms of their social class, occupation, education, age, sex, residence, and urban orientation. The later chapters examine a recorded corpus for linguistic variables that are phono-lexical (palatal glides), phonological (consonant cluster simplification), morphological (past-tense inflection), and syntactic (pre-verbal tense and aspect marking), using quantitative methods of analysis (including Varbrul). The Jamaican urban mesolect is portrayed as a coherent system showing stratified yet regular linguistic behavior, embedded in a well-defined speech community; despite the incorporation of forms and constraints from English, it is quintessentially creole in character.