Even before the conclusion of World War II, the alliance between America and Britain had proven to be one of the most formidable in history, yet there were also constant tensions and disagreements that threatened to pull the nations apart. Based on considerable archival research on both sides of the Atlantic, Niall Barr considers the high-level strategic decisions, the rivalries. and personalities of Patton, Eisenhower, Churchill, and Montgomery, along with a host of other lesser-known figures who contributed to this vital collaboration. Tracing relations between the countries back to the French and Indian War, Barr also assesses how two very different armies learned to live, work, and fight together.