"It is perhaps unsurprising that phrenology already occupies a fairly well-explored area in the history of science. This valuable and engaging book, however, breaks new scholarly ground. James Poskett uses the material cultures of phrenology—such as skulls, letters, and photography—to generate an interconnected transnational history that transforms a familiar pseudoscience into a complex and multifaceted global process. As it examines phrenology’s many global pathways, interchanges and permutations, Materials of the Mind remains attuned to power but explicitly works against the constraints imposed by units of analysis such as nations and empires, offering instead a materially based and iterative model for a global history of science. As a global history, this work offers a wide-ranging and erudite analysis of how transnational flows of material and material cultures shaped phrenology. . . . Every chapter of this book is distinguished by impressive archival work across many collections in numerous global locations and languages. Detail, references, and illustrations abound, supporting Poskett’s fundamental commitment to exploring material culture’s role in shaping a global history of science. . . . As both an exploration of phrenology specifically and as a scholarly work interested in advancing the question of what it means to write a global history of science, Materials of the Mind comes out ahead."