Given the phenomenal fame and commercial success that the Beatles knew for the entire course of their familiar career, their music per se has received surprisingly little detailed attention. Not all of their cultural influence can be traced to tong hair and flashy clothing; the Beatles had numerous fresh ideas about melody, harmony, counterpoint, rhythm, form, colors, and textures. Or consider how much new ground was broken by their lyrics alone -- both the themes and imagery of the Beatles' poetry are key parts of what made (and still makes) this group so important, so popular, and so imitated. This book is a comprehensive chronological study of every aspect of the Fab Four's musical life -- including full examinations of composition, performance practice, recording, and historical context -- during their transcendent late period (1966-1970). Rich, authoritative interpretations are interwoven through a documentary study of many thousands of audio, print, and other sources.