Focusing on the frequently neglected influence of rhythm on variation and change in English grammar, this book provides a groundbreaking study of interactions at the interface between phonology and morphosyntax. It refines available descriptions of grammatical phenomena by examining the explanatory force of the avoidance of adjacent stressed syllables. The main, empirical part presents twenty detailed analyses of a representative set of structures, most of them combining a synchronic and a diachronic perspective. The analysis is based on an extensive collection of electronic corpora covering the sixteenth to twentieth centuries. A theoretical discussion of implications for linguistic models such as Optimality Theory and spreading activation networks rounds off the volume.