In Ballast: Laden with History, the archaeologist Mats Burström charts how ship ballast helped to shape the world we live in. Until only very recently, ships were ballasted with sand, gravel, stone, or rubble to give them stability, and when they no longer needed the extra weight, it was dumped. The result was that huge quantities of ballast were shipped to new places and new continents. Ballast was often reused, sometimes in surprising ways. This is the first comprehensive account of ship ballast, so long overlooked, and now finally recognized for its diverse and exciting history.