There is no country in the world where as many different languages are spoken as in New Guinea, approximately a fifth of the languages in the world. Most of these so-called Papuan languages seem to be unrelated to languages spoken elsewhere. The present work is the first truly comprehensive study of such a language, Hua. The chief typological peculiarity of Hua is the existence of a 'medial verb'construction used to conjoin clauses in compound and complex sentences. Hua also shows a fundamental morphological distinction between coordinate and subordinate medial clauses, the latter are not 'tense-iconic', the events they describe are not necessarily prior to the event described in later clauses. Moreover their truth is always presupposed. The distribution and behaviour of a post-nominal suffix - mo provides insights into the nature of topics, conditional clauses, and functional definitions of the parts of speech. In phonology, the central rules of assimilation are constrained by the universal hierarchy of sonority, which may, however, be derived from binary features. These are some of the areas in which the grammar of Hua is unusually perspicuous. The present work aims at a standard of completeness such that it would be a useful reference work for research in almost any theoretical topic.