Book excerpt: The past twenty-five years have brought a dramatic expansion of scholarship in maritime history, including new research on piracy, long-distance trade, and seafaring cultures. Yet maritime history still inhabits an isolated corner of world history, according to editors Lauren Benton and Nathan Perl-Rosenthal. Benton and Perl-Rosenthal urge historians to place the relationship between maritime and terrestrial processes at the center of the field and to analyze the links between global maritime practices and major transformations in world history. A World at Sea consists of nine original essays that sharpen and expand our understanding of practices and processes across the land-sea divide and the way they influenced global change. The first section highlights the regulatory order of the seas as shaped by strategies of land-based polities and their agents and by conflicts at sea. The second section studies documentary practices that aggregated and conveyed information about sea voyages and encounters, and it traces the wide-ranging impact of the explosion of new information about the maritime world. Probing the political symbolism of the land-sea divide as a threshold of power, the last section features essays that examine the relationship between littoral geographies and sociolegal practices spanning land and sea. Maritime history, the contributors show, matters because the oceans were key sites of experimentation, innovation, and disruption that reflected and sparked wide-ranging global change. Contributors: Lauren Benton, Adam Clulow, Xing Hang, David Igler, Jeppe Mulich, Lisa Norling, Nathan Perl-Rosenthal, Carla Rahn Phillips, Catherine Phipps, Matthew Raffety, Margaret Schotte.