Relatively little historical-comparative work has been done on the languages of the vast Trans New Guinea family, and this book breaks new ground with a study of the Binanderean languages of the Morobe and Oro Provinces of southeast mainland Papua New Guinea. The author investigates the phonological history of the group and reconstructs the sound system, core lexicon, and some bound morphology of Proto Binandere. She postulates an inventory of Proto Binandere segmental phonemes, together with sequences of regular sound changes leading to the reflexes of these phonemes in the daughter languages. The shared innovations which these changes represent allow the construction of a family tree. The author also discusses the occurrence of parallel phonological changes among Binanderean languages. Some aspects of the phonological and lexical reconstructions and changes attributed to Proto Binandere and later interstages are then examined, including the neutralisation of voiced plosives and prenasalised plosives, the possible role of pitch and stress, and irregular sound changes (assimilation, metathesis, and loss). Innovations in verbal and nominal morphology are investigated as an additional source of evidence for subgrouping. Binanderean lexical and morphological data are then compared with those of Guhu-Samane, a language long considered to be the closest external relative of the Binanderean family. Evidence of this relationship is presented, along with grounds for excluding it, from the family. Finally, the author gives lexical comparisons between Binanderean and four other putative eastern New Guinea subgroups of the Trans New Guinea family, and shows that Binanderean is indeed a likely member of the family. Based on the location of the Trans New Guinea subgroup which appears to display the strongest lexical resemblances to Binanderean, as well as on the location of Guhu-Samane, she hypothesises a northerly dispersal centre and a southeastern migratory direction for the Binanderean-speaking peoples.