Abstractfins paper discusses the question to what extent morphology is an autonomous module ol the grammar. Alter a general survey and discussion of the issues involved, a detailed analysis is given ol' allomorphy phenomena. It is argued thai these phenomena support the relative autonomy of morphology since the formal regularities involved cannot be deduced from phonological or syntactic principles. In addition, a proper account of these formal regularities requires reference to the form ot paradigmatically related words. Thai is, paradigmatic relations play a crucial role, which is another characteristic property of the morphological module.