This book is an exploration of the syntax of external arguments in transitivity alternations from a cross-linguistic perspective. It focuses particularly on the causative/anticausative alternation, which the authors take to be a Voice alternation, and the formation of adjectival participles. The authors use data principally from English, German, and Greek to demonstrate that the presence of anticausative morphology does not have any truth-conditional effects, but that marked anticausatives involve more structure than their unmarked counterparts. This morphology is therefore argued to be associated with a semantically inert Voice head that the authors call "expletive Voice". The authors also propose that passive formation is not identical across languages, and that the distinction between target vs. result state participles is crucial in understanding the contribution of Voice in adjectival passives. The book provides the tools required to investigate the morphosyntactic structure of verbs and participles, and to identify the properties of verbal alternations across languages. It will be of interest to theoretical linguists from graduate level upwards, particularly those specializing in morphosyntax and typology.