The book is a generative study of a number of English and Polish processes of suffixation. It focuses on various constraints on such processes. The allomorphy of English inflection is shown to follow from language-specific constraints on syllable structure. English derivational suffixes are shown to be crucially sensitive to the morphological make up of their bases - the majority fails to attach to a suffixed stem, while the rest attaches to a well-defined subset of all suffixed stems. Thus some major tenets of the current mainstream generative theory of the lexicon (Affix Ordering Generalization and Bracket Erasure Convention) are called into question. A detailed discussion of verbalizing processes of contemporary Polish reveals that rules of suffixation are subject to constraints on their bases the proper formulation of which specially involves the distinction root/stem. Markedly distinct characteristics of root-based and stem-based morphological rules are thoroughly discussed. The productive deverbal morpholocial processes in Polish are shown to require access to more than one component formative in the base, which seriously undermines some constraints advanced in the literature (Adjacency condition, Atom condition).