IN HIS PREVIOUS books Mark Girouard, the eminent British architectural historian, has concentrated much of his attention -- not to mention his wit, erudition and stylistic elegance -- on the country dwelling places of the prosperous and powerful, but in Cities & People he casts a far wider net. This generously illustrated book "is concerned with Western cities from the Middle Ages up to the twentieth century, in terms of who did what, why, where and when," and as such amounts to an informal history of the modern city. Though modest in his claims for the book -- "I am not conscious of having any particular message or theory" -- Girouard in fact accomplishes a great deal in it; for anyone who cares abouities, or anyone who seeks to understand them, Cities & People is invaluable reading.

Those who hate or fear cities must be warned at the outset that Girouard is an ardent partisan of urban life. He loves "the sense of drama in its widest sense: the sense that many varieties of human life are concentrated on one stage," and he most loves those cities which have welcomed and harbored the greatest diversity: Rome in the 16th and 17th centuries, where "it was possible to live the life one chose"; Paris in the 19th century, "the epitome of all the modern city had to offer"; Chicago and New York in the same century, both of them dynamic and capacious. Consider by contrast the city of the Middle Ages:

"It is hard for us to get any concept of the atmosphere of a medieval town. The life- style was essentially orthodox; there was as little room for dissent as in any town under a strict Communist or Islamic regime today. It was generally accepted that there were right beliefs and right ways of behaving, and that any deviation from these was punishable, often by flogging, mutilation or death. The guardians of orthodoxy were the Church and the civic government. Those who thought differently from the Church were heretics, and those who thought differently from the government were rebels. . . . In Florence the cook who cooked a wedding dinner had to send the menu in advance to the city officials, so that they could check that it was not too lavish. The bride could ride to church on horseback, but had to return on foot, under pain of a fine. In Siena in 1425 women were forbidden to wear silk clothes, or a train, or crepe lining which accentuated the curves of their bodies. In Nuremburg, workmen were fined for parting their hair in a forbidden manner."

Yet in these hermetic, claustrophic cities and towns the seeds of the modern city were planted. As Europe emerged from the Dark Ages, as trade revived and people began to awaken from the long slumber, cities arose -- the greatest of them, "the biggest, richest and most sophisticated city in the world," was Constantinople -- and, within them, rudimentary institutions took shape: markets gradually turned into shops, centers of financial activity formalized themselves into banks, separate business and trade districts evolved, hospitals were constructed, academic activity intensified, and basic city services were undertaken. Among the latter were "the cleaning, paving, draining, widening and even lighting of streets, and the creation of new ones; the formation or enlargement of squares; the building of bridges and wells; the supply of water and grain; the building of quays and the provision of cranes on them; and the building of walls and fortifications" -- almost all of which, in one form or another, have been the obligations of city government ever since.

But it was in the Renaissance that the city really came to life. Beginning with the rebuilding of Rome, the cramped medieval city began to disappear; in its place arrived the city of great vistas, the city in which spectacle was seen to be an essential part of life. One after another these cities parade through Girouard's account: Rome, Antwerp, Gdansk, Amsterdam, Paris, London, and at last L'Enfant's Washington, "arguably the most brilliant town plan ever conceived." Though these cities tended to grow randomly, there was about them more order and plan than the Middle Ages had ever imagined, and there was also vastly greater diversity and sophistication. In a brilliant chapter called "The Uses of Leisure," Girouard argues that in the modern city a crucial influence appeared:

"The crowds of fashionable people promenading in coaches on the Cours la Reine or walking in the Tuileries gardens represented a new development in the European city. They formed what was later to be called 'society,' but to begin with tended to be referred to as 'polite society,' the 'beau monde' or 'people of quality.' Society had no formal existence and no legal powers, but by the eighteenth century many outsiders were desperately anxious to belong to it. It was a group of people who did things together, entertained each other, wore particular clothes, and talked, walked, behaved and decorated their houses in a particular manner. Any society had an inner ring, members of which were informally recognized as arbiters of who or what was acceptable. Whether or not someone was invited to their houses was the basic test of whether he or she belonged. Society became an extremely important element in cities, because it produced more than coaches and promenades. Theaters, opera houses, pleasure gardens, assembly rooms, race-courses, coffee-houses, shops, entire neighborhoods and ultimately entire towns grew up to cater for it."

As society came to prominence, outside the cities there was a reaction against its excesses, as well as those of the urban lower orders: "Babylon was in the air. 'The modern Babylon' became a familiar nickname or journalistic clich,e for London, and, inevitably, as Paris grew, it too began to be called Babylon." For many these modern cities were too large, too dirty, too dangerous, too steeped in luxury and wickedness. "The belief that the country is basically good and the city basically wicked can be traced deep into the past," Girouard writes, "but its particular modern form stems from the reaction against the many and undeniable horrors of big nineteenth-century cities." In reaction against these horrors many "city beautiful" movements arose in Europe and the United States, which attempted to prettify the city at the expense of its diversity and dynamism; much of the largely disastrous "urban-renewal" period can be traced to these movements.

EVEN IN THE relatively sophisticated and tolerant climate of today, the city is widely regarded with suspicion and contempt; hence the popularity of the suburbs, which seem to offer the compromise of ready access to the city's benefits without exposure to its dangers. Thus, too, the emergence of two new kinds of cities: in the first "a single high-density downtown, culminating in a burst of skyscrapers, is surrounded by a girdle of motorways, beyond which low-density suburbs stretch to the horizon"; the second is the "low-density multi-center city." The first is called Houston, the second Los Angeles; Girouard prefers Los Angeles, which "can produce much of the complexity and variety of a conventional city" and "is a more sensible model, particularly as improving technology makes the diffusion of work increasingly practicable."

For those of us who love the old 19th-century city, the possible dominance of the Los Angeles style is not especially happy news, but perhaps the central lesson we learn from Cities & People is that the nature of cities is forever changing and that the fortunes of individual cities rise and fall due to influences beyond our control. Another lesson is that if the look, shape and feel of cities evolve in unpredictable ways, and at terrible costs to those cities that cannot adapt to change, the city itself remains intact, with what Dr. Johnson called its "wonderful immensity" as vigorous as ever. Whatever form it takes, a city is still a city, and thank heavens for that. Thank Mark Girouard, too, for paying it such handsome, loving tribute.