This monograph focuses on an interesting typological property shared by four languages: the ungrammaticality of multiple wh-questions in Irish, Berber, Italian and Somali. It contains a broad discussion of data related to the grammar of wh-questions, a comparative analysis of wh-constructions in the four languages, and a theoretical account for the observed phenomenon. The analysis is based on the minimalist syntax theory as developed by Chomsky since 1995. It takes up the standard assumption that wh-phrases are typical representatives of elements bearing new information, in theoretical terms referred to as information focus. Most importantly, in the languages without multiple wh-questions the information focus is licensed in a unique syntactic position. The basic claim is that languages with unique focus are languages without multiple wh-questions. The analysis makes possible the classification of the languages without multiple wh-questions into the crosslinguistic typology of wh-constructions. Furthermore, this book is a contribution to the better understanding of information structure in natural languages, especially of focusing phenomena.