Meghna Chakrabarti interviews Craig Fairman about his book *This Vast Enterprise*, which reexamines the Lewis and Clark expedition by highlighting overlooked figures like Sergeant John Ordway, enslaved men York and Sacagawea, and Native leaders Black Buffalo and Biahito. Fairman debunks the myth that the Louisiana Purchase preceded the expedition, revealing it as a massive, politically contentious military operation. The discussion explores how these diverse individuals shaped the journey’s diplomatic and scientific outcomes, challenging the traditional narrative centered solely on Lewis an…