Taking extra-vagans literally (Lat. 'wandering outside, out of bounds'), this volume comprises nine case studies on extravagant morphology ranging from pattern-extending derivational processes via theory-challenging compounding processes to interface-straddling morphosyntactic phenomena. As a heuristic approach, morphological extravagance captures word-formation processes characterised by constraint violations, interface phenomena as well as borderline phenomena not easily reconcilable with traditional postulates of morphological accounts. In this regard, the notion of extravagance allows for an exploration of rule-bending language use both empirically and theoretically. The volume makes a valuable contribution to studies on morphological variation, which has only recently seen a renewed and growing interest in morphological phenomena that challenge morphological frameworks. The volume is of interest to all researchers who seek to gain a broader understanding of the mechanisms and factors at work in morphological variation and who are interested in the reassessment of morphological theorising in light of empirical data.