This monograph studies issues of current minimalist concern, such as whether differences in the expression of argument and syntactic structure can all be attributed to the parameterization of specific functional heads. In particular, this book studies in-depth the extent to which variation in the expression of causation, available both intra- and crosslinguistically, can be accounted for by appealing only to the microparameterization of the causative head, Cause, as previously argued for by linguists such as Pylkkanen. It concludes that the microparameterization of Cause may explain some major characteristics associated with causatives, but it cannot be regarded as the only explanation behind variation in these structures. The book includes relevant discussion on argument structure and looks in detail at languages, such as the Uto-Aztecan Hiaki, that have not received much attention before. It is mostly intended for an audience interested in theoretical approaches to argument structure and variation.