The main concern of this study is to make a foreign policy analysis of the Ottomans and to try demonstrating how policy-making might have affected the Ottoman take during the Thirty Years War (1618-1648). Under light of former studies and primary evidence, the present study tries to prove that there were concrete instances of Ottoman military intervention in the war. Second, it will seek to answer why the Ottoman Empire should be regarded as a player on the scene of this continental political crisis, even though they remained largely non-participant. Accordingly, the study points out to the psychological effect of the Ottoman power on the European states, relying on contemporary diplomatic reports. Lastly, the book presents the study of a primary source: The final ambassadorial report of Paul Strassburg, the envoy of Swedish King Gustav II Adolph in Constantinople in 1632 and in 1633, is translated from its original Latin transcription and evaluated in its historical setting.