Multiple interrogatives, questions with multiple who-phrases (e.g. Who bought what?), have long presented analytical challenges for linguistic theory. This monograph presents a new theoretical and experimental study of this construction. The theoretical findings concern the interaction between superiority effects, subject-auxiliary inversion, and the distribution of pair-list and single-pair readings cross-linguistically. The author also examines multiple interrogatives under sluicing (i.e., clausal ellipsis), presenting new arguments for the deletion analysis of sluicing. The author also reports the results of several experimental studies on how children acquire the language-specific properties of multiple interrogatives in English, Russian, and Malayalam. The results suggest a correlation between the acquisition of multiple interrogatives and the acquisition of contrastive focus, which has been independently motivated in syntactic literature. The monograph will be of interest to linguists concerned with syntax, semantics, and language acquisition, as well as readers who are interested in a comprehensive theory of language in general.