The book lifts the veil of mystery about Lend-Lease. It objectively sets out the history of economic relations between the United States of America, Great Britain and the Soviet Union during World War II. Based on the analysis of archival data, statistical materials, generalization of facts set out in little-known publications, the author determined the most reliable cost of Lend-Lease supplies and calculated their significance taking into account the present value of money. Characteristics of the brightest and most controversial politicians of the 20th century are given. Their role in the preparation and implementation of the deal of the century is revealed. The book is equipped with a large number of applications that are informatively valuable and useful for the reader to understand the events that happened 60 years ago. For students and teachers of economic universities and departments, as well as for a wide range of readers.