Who is What and What is Who: the Morphosyntax of Arabic WH is a comprehensive book that deals with one of the most controversial phenomena in syntax, Parametric Variation. In particular, the book offers an in-depth, micro-parametric analysis of all the strategies used in wh-question formation and the variation in these observed in modern Arabic dialects. Unlike traditional analyses of this element of Arabic linguistics, the approach developed here is based on the morphology-syntax interface, as well as the syntax-phonology interface in addressing parametric variation. The findings of the study detailed in this book are also placed in perspective through an examination of the possibilities that Universal Grammar offers languages in terms of building wh-dependencies, including topicalisation, relativization and variable binding.