Variation is among the most fundamental and essential musical processes. Yet, variation as a form has often been overlooked and undervalued for several reasons, including its formally fragmentary nature and its heavy reliance on melodic decoration. Across forty-two newly commissioned essays by forty-six authors from around the world, The Oxford Handbook of Musical Variation seeks to restore faith in this traditionally underemphasized form. It also examines variation as a technique apart from variation form--a technique that is integral to music of virtually all styles, forms, and genres. While exploring the traits of musical variation that have proven consistent over time, the volume also considers the diverse ways in which those traits have been treated, analyzing myriad works and their unique deployment of variational techniques.This handbook examines both sectional and continuous variation forms, from Heinrich Biber to Samuel Coleridge-Taylor. Subtopics include music cognition, Schenkerian approaches, hermeneutics, and variation in songs and sonata form. It surveys techniques such as developing variation, thematic work, contrapuntal treatment, leitmotifs, and thematic recurrence. It also considers variations that span the movements of a work (cyclicity) and even that span different works entirely (intertextuality). The concluding section delves into the teaching of variation, especially from historical vantages. Traversing virtually the entire history of Western music, from Renaissance music to jazz, The Oxford Handbook of Musical Variation is a multifarious exploration of the most cardinal of compositional practices and encompasses the plurality of topics and musics that characterizes modern musicology.