This is the first detailed English-language study of the Spanish Republic's forces in the devastating Spanish Civil War of 1936-39 - an army supplied and supported by Stalin's Soviet Union, which also attracted volunteers from all over Europe and North America.

Alejandro de Quesada is a Florida-based military history writer, an experienced researcher, and collector of militaria, photos and documents. He runs an archive and historical consultancy for museums and films as a secondary business. Alejandro has written over 100 articles and over 25 books, including several for Osprey, and is a leading authority on Latin American subjects.

Stephen Walsh studied Art at the North East Wales Institute and has worked as a professional illustrator since 1988. Since then he has illustrated a variety of books and games including Settlers of Catan. His projects for Osprey include such diverse subjects as the battle of Otterburn, the Chinese army from 1937 to 1949 and the US Home Front in World War II.