The domains of divergence among current conceptions of inflectional morphology appertain to five fundamental issues. What are the basic units in terms of which inflectional morphology is defined? Is the morpheme a theoretically significant concept? What sort of structure do inflected word forms possess? Do they have a quasi-syntactic hierarchical structure that determines their semantic composition? What is the relation between concatenative and nonconcatenative inflectional patterns? Are they equivalent alternatives for realizing morphosyntactic content or is affixation pre-eminent, sometimes triggering nonconcatenative operations of secondary status? What is the relation between a word form’s morphosyntactic properties and their inflectional exponents? Are exponents lexically listed with their properties, or do a word form’s morphosyntactic properties trigger rules that specify their exponents? Finally, what distinguishes inflection from word formation? Are these discrete components? Is their difference purely one of function? Competing answers to these questions are examined in the light of empirical evidence.