These studies present various aspects of a long-running enquiry into the development of government, the state and absolutism in early-modern Spain, distinctively based on thorough use of central and local manuscript sources. In the first section, five papers on government and institutions cover the Spanish Council of War under Philip II, the military-administrative bureaucracy of Habsburg Spain, an authoritative general history of Spanish government under Philip IV and the nature of Castilian absolutism, together with a detailed review paper on the legal process and sociology of law in early-modern Castile. The second section reprints four major articles re-interpreting the position of representative institutions during the period of Habsburg absolutism. The first two of these, on the Castilian Cortes between 1590-1665, were the first serious studies of the topic for over a century, and have been instrumental in re-directing further historical work in this subject. Their conclusions are reinforced by a very detailed study of representatives to the Cortes, which appears for the first time in English, and a comparative study of the Castilian Cortes and the English Parliament.