Relational Morphology is based in the mentalistic perspective of the Parallel Architecture (Jackendoff 2002). Morphology is the grammar of word-sized pieces of structure, comprising morphosyntax and its interfaces to phonology, semantics, and phrasal syntax. Many morphological patterns are nonproductive; their instances must be listed in the lexicon. They therefore resist formulation in terms of traditional procedural rules; declarative schemas prove more adequate. Productive schemas can build novel forms; nonproductive schemas cannot. Instead, they motivate relations among lexical items. Lexical relations are often described in terms of inheritance; this chapter proposes enrichments that render inheritance more adequate for morphology. Productive schemas too can motivate lexical relations. Hence they are just like nonproductive schemas except that they have ‘gone viral’. The authors conclude that the focus on productive patterns has deflected attention from a more basic issue: the architecture of the lexicon, the structure of lexical items, and the relationships among them.