Since the publication of Kirti N. Chaudhuri’s Trade and Civilisation in the Indian Ocean (New York, 1985), historical studies of the Indian Ocean World (iow) have grown exponentially. Coming to grips with this vast oceanic space has challenged subsequent generations of historians to think creatively about how best to address its great diversity in both time and space. An important feature of this recent scholarship is its interdisciplinarity. In the volume under review, Gooding takes an innovative approach to what, in some hands, might have been limited to a regional East African study of this historiographically neglected zone by locating Lake Tanganyika as a frontier of the iow. By defining the Indian Ocean littoral as the core of this watery world, he boldly proposes that this great African lake lay at its frontier. Specifically, in this analysis, he depicts a dynamic interaction that links the Swahili coast and the lakeshore littoral through the integrating element of the ivory trade. As he writes, “This book is about how these physical lines of connection developed and the roles that littoral and inland populations around Lake Tanganyika had in shaping them” (3).The book opens with an introduction discussing “Lakes, Oceans and Littorals in History” in which Gooding makes his case. The body of the text is divided into two parts. The first, entitled “Demarcations of Space,” includes three chapters—“The Growth of Emporia,” “Changing Land Use in a Changing Climate,” and “Traversing the Lake.” Part II is divided into four chapters—“Competition and Conflict on the Western Frontier,” “Global Commodities in East African Societies,” Structures of Bondage,” and “An Islamic Sea.” In each of these chapters, Gooding strives to demonstrate the numerous ways in which the changes wrought by the expansion of the ivory trade worked to connect the Swahili coast to the lakeshore and to transform the lakeshore’s society and culture, especially after about 1860.Some of Gooding’s assertions are more speculative than demonstrable—an evidentiary challenge that is familiar to historians of precolonial Africa—but his thesis nonetheless demands serious attention. That said, although he sets his study in a wide East African context and relates it to parallel examples from the broader iow, he misses the opportunity to consider the comparative possibility of an earlier interior African frontier of the iow—the auriferous region of the Zimbabwe plateau in its relationship to the Sofala coast (today, southern Mozambique). He might also have contrasted the evolution of the town of Ujiji into the main entrepôt for coastal links on the eastern side of Lake Tanganyika with the development of Nkhotakota on the western side of Lake Malawi, given their contemporaneous chronologies.The author draws from a wide range of sources, including archaeology, anthropology, oral history, and environmental studies, but he admits that the bulk of his evidence comes from reading the classic nineteenth-century European explorer and missionary accounts, whether published or located in various archives. Nevertheless, he recognizes the biases of his European sources and is meticulous in his reading of them. He is also careful in his use of oral sources, where he points to the problems of feedback and the positions of his informants (172–176).Gooding brings these elements together in each chapter of the book, but his most interesting discussions concern slavery and Islam. His most vigorous use of interdisciplinary sources and methods, however, is in his chapter about the effect of climate change (rainfall and lake levels) on what he defines as an agricultural “revolution” during the nineteenth century. As he argues, “Climate and climatic change are crucial for contextualizing this agricultural revolution” (65). Thus, he reveals the important intellectual influence of his academic home at the Indian Ocean World Centre at McGill University, where a major thematic focus is on “Appraising Risk, Past and Present” in the iow. Readers of this journal will find that chapter especially valuable.