This series provides critical studies of key figures in international political history since 1500. The books are not personal biographies, although they do contain biographical information, but are succinct interpretive essays on the career. Gustavus Adolphus (King of Sweden 1611-1632) was a key figure in 17th century European history. He was the principal upholder of the Protestant cause in the 30 years war and was a great administrator as well as a brilliant soldier, whose toleration and reforms helped to define the development of the modern state. This is a concise study of Gustavus Adolphus's career now revised and reset to take into account new research since the book was first published in 1973. It is aimed at undergraduate courses in 17th century history and European history.