Today, the Kordofanian family of the Niger-Congo phylum remains one of the most poorly researched language families in Africa and worldwide. This book makes two descriptive grammars available to the scientific community, respectively Tira and Otoro (both of which belonging to the Heibanian branch of Kordofanian) and is therefore a most welcome publication. The author of those grammars, Roland C. Stevenson (1915‒1991), is a member of the Church Missionary Society, who first arrived in Sudan in 1937 and soon got involved in the study of various Sudanese tongues. He devoted his PhD (Stevenson 1956-57) to the languages spoken in the Nuba Mountains, a region which is the home area of all attested Kordofanian languages. As “descriptive and comparative work on Kordofanian languages is still in its infancy” (Schadeberg 1989: 79), Stevenson’s abundant linguistic production remains one of the main sources (and in some cases the only one) available for many Kordofanian languages. The editor of these grammars, Thilo Schadeberg, is one of the very few linguists to have regularly worked and published on Kordofanian languages (e.g. Schadeberg 1981a/b, 1989) since the second half of the XXth century. As explained in the preface of the book, Stevenson wrote his Tira (TI) and Otoro (OT) grammars in 1942 and 1943 respectively. However, these existed only as typescripts and it is thanks to Schadeberg’s efforts that “the data and analyses” they contain are “presented here [i.e. in this book] for the first time in print” (p. viii).