The ""prisoner"" was Queen Juana of Spain, daughter of Ferdinand and Isabella, whose madness, Schoonover claims, was for many years a convenient and contrived ""out"" for those who found it inadvisable to let her reign. But the imprisonment, imposed by her mother, her father, her son, ended in actual madness- and most of her life was spent in luxurious isolation, while Europe was in the throes of power politics at their peak. It is an extraordinary picture of courts of Europe -- from Spain to Flanders to France -- while the distant Emperor of Austria and the Holy Roman Empire pulled strings to circumvent Spain's rulers, and they in turn undercut France and England. The story revolves around Juana's earlier years, while she still fought to regain her freedom, and the last fifty years of darkness are simply a closing epoch. Schoonover sustains the interest of the reader, presents a vivid portrait of an era, and makes figures of history live.