The most comprehensive work on dissimilation (the avoidance or repair of combinations of similar sounds) to date, this book proposes a novel analysis that handles dissimilation as the avoidance of surface correspondence relationships. It draws on recent work in Agreement By Correspondence to show that dissimilation is a natural outcome predicted by the same theory of Surface Correspondence. The theory is developed in more detail than ever before, and its predictions are tested and evaluated through ten in-depth analyses of diverse languages from Quechua to Kinyarwanda, together with a typological survey of over 150 dissimilation patterns drawn from over 130 languages, from Acehnese to Zulu. The book redefines the core of Surface Correspondence theory to a level of formal specificity and theoretical precision surpassing previous work. The book's findings are made more accessible by numerous examples featuring data from 47 languages from around the world.