One surprising outcome of the Russo-Japanese War of 1904-5 was that, although Russia was humiliatingly defeated, by 1916 Russia and Japan had become allies. This book provides a detailed analysis of how this remarkable turnaround came about. It traces the evolution of relations between the two powers through the conclusion of three public and secret agreements in 1907, 1910, and 1912, and the controversial secret alliance of 1916. The book argues that careful examination of complete records of negotiations from both sides definitively proves the case for Germany, not the United States, as the target of the secret treaty. Based on meticulous examination of documents in both Russian and Japanese foreign policy archives, it charts diplomatic developments, explores how Japanese and Russian thinking evolved, and assesses the wider international impact of the new alliance.