Book excerpt: The field of morphology is particularly heterogeneous. Investigators differ on key points at every level of theory. These divisions are not minor issues about technical implementation, but rather are foundational issues that mold the underlying anatomy of any theory. The field has developed very rapidly both theoretically and methodologically, giving rise to many competing theories and varied hypotheses. Many drastically different and often contradictory models and foundational hypotheses have been proposed. Theories diverge with respect to everything from foundational architectural assumptions to the specific combinatorial mechanisms used to derive complex words. Today these distinct models of word-formation largely exist in parallel, mostly without proponents confronting or discussing these differences in any major forum. After forty years of fast-paced growth in the field, morphologists are in need of a moment to take a breath and survey the drastically different points of view within the field. This volume provides such a moment.