Detailed information about Spain from a 1998 publication of the Federal Research Division of the Library of Congress. You can find information about the history, geography, government, economy, and people of Spain.

This website provides information about Spain's economic, political and military decline during the 17th century. The site discusses Philip III & IV, the plague, Count de Olivares, and the rapid losses of the military.

Wikipedia gives a great account of the War of the Spanish Succession, with links to related information. The article discusses the origins, the progression of the war, the Peace of Utrecht, as well as the participants and major generals.