A PALACE FOR A KING: The Buen Retiro and the Court of Philip IV, by Johnathan Brown and J.H. Elliott (Yale, $29.95).

The Buen Retiro, a palace built in the 1630s when Madrid was in transition from a provincial city to the captial of a world empire, has long been in ruins and has attracted little attention until now. It once embodied ambitions similar to those lavished on Versailles, but King Philip IV, for whom it was built, was no Louis XIV. During his reign this palace became a symbol of bad government, derisively nicknamed "the chicken coop." Properly interpreted, as it is in this volume through the collaboration of an art historian and a political historian, the story of this building provides insight into the events of the early 17th century when the Spanish Empire passed its peak and began its long decline. The focus is on the man behind the construction of the palace, the king's favorite, Don Gaspar de Guzman, Count-Duke of Olivares, whose "powerful if disorderly mind" conceived ambitions similar to Richelieu's in France but ran into a series of political, economic and military disasters that ruined his health and destroyed his plans. This book is not a history of art so much as history seen partially through art. THE REIGN OF CHIVALRY, by Richard Barber (St. Martin's, $27.50). The man in shining armor, mounted on a horse and bearing a lance, has become an archetypal figure in our collective mind: symbol of strength, protector of society, model of a lofty ideal of service. Barber's study traces this ideal and its examplars from the time of Charlemagne through the heyday of chivalry in the 13th and 14th centuries to its gradual decline as warfare shifted to a siege mentality and crossbows and gunpowder made heavy armor obsolete. Besides the military role of the knight, Barbar traces the religious overtones of chivalry, its social role and the vast literary output on the subject, from the troubadours, "The Cid" and "The Song of Roland" through the Arthurian cycle and up to the idealized novels of the Victorian era. The abundant and excellent illustrations will be the first attraction for most readers, but the book's enduring value lies in a thoughtful, readable text, accessible to a general readership but quite comprehensive in its treatment of a complex subject. ATLAS OF MEDIEVAL MAN, by Colin Platt (St. Martin's, $22.50). The term "medieval" usually evokes a sense of European parochialism, but it is splendidly transcended in this survey of the world's cultures between the years 1000 and 1500. Here the pictures are the main attractions, and the text focuses on generalizations more than details, but it provides a synoptic view to put the world's cultures in chronological context. Platt's treatment correlates the Bayeux Tapestry chronologically with the golden age of Sung painting in China, the carving of Toltec figures in Latin America and the building of Pueblo "apartment houses" further north. In the 14th century, he finds striking contrasts "between the disillusioned sophistication of the painters of Byzantium and China on the one hand, and the vigorous exuberance of the craftsmen-potters of Ife in Nigeria on the other." The rise of Zen Buddhism in Japan, the spread of the Ottoman Empire, the building of walled cities in Peru, the removal of the papacy to Avignon are all familiar, disconnected events. Their treatment in a single section of the book, because they were contemporary, gives the reader a view of a vanished world that could have been held by no one who was living at the time.