A royal fortress, a royal palace, a royal prison"" -- the Tower of London has been these and much more. At one time or another it has functioned as the principal depository for England's public records, a national mint for both England and Ireland, a major arsenal, and even a large zoo, complete with lions, tigers, and monkeys. Derek Wilson's readable book not only relates the history of London's, and perhaps the world's, most famous tower, but places that history within the larger context of English history. The Tower was begun by William the Conqueror in order that the strategic center of London might ""be permanently overawed by the Norman presence."" In 1140 King Stephen decided to hold his court at the Tower, and by the reign of Henry III (1217-1272) the Tower had become ""for the first time a major royal palace."" This close personal contact with English sovereigns continued up to the death of Henry VIII in 1547. After Henry's demise, royal visits declined, and the Tower's special association with the monarchy began to diminish. However, the Tower ""continued to play a vital and complex role in the life of the nation,"" but more as Ordnance Office, mint, public-records storehouse, and, increasingly, international tourist attraction. Most readers, of course, think of the Tower as a prison and execution site. Wilson deftly recounts the stories of the Tower's famous captives: the murdered princes, Lady Jane Grey, Sir Thomas More, Anne Boleyn, Catherine Howard, Sir Walter Raleigh, and many, many more. He is good, too at describing the Tower's changing architectual face. A series of useful drawings supplements this aspect of his text and indicates the evolution of the Tower's buildings at various stages in its history. Agreeable and informative.