Scattered inconspicuously among these glossy anecdotes and photographs of palaces and castles and their inhabitants is evidence that belies the entire assumption on which the institution of aristocracy -- and this book -- is based.

In an early chapter, Lacey notes that European titles were originally military, dukes being high commanders, earls viceroys and so on, and that these are no more hereditary than military ranks are today. Only later did owning land, a military necessity when the basic equipment of the warrior was his horse, become the distinguishing qualification of aristocracy.

Elsewhere, Lacey attributes Napoleon's victories to his having defied French military tradition to choose his officers by ability, rather than birth, thus furnishing evidence that such skills do not descend neatly in bloodlines. Then Napoleon went right ahead and resurrected the original fallacy by awarding hereditary titles to his officers in recognition of their prowess.

And so the aristocratic idea survives, blithely defying logic and even principle. Our own democracy, founded in rebellion against the very concept that birth, rather than individual achievement, determines a person's worth, abounds in unseemly illustrations of its attraction. Otherwise upright American citizens just can't seem to keep off their knees in front of visiting royalty.

But, then, of course, we all know that it isn't the presumed inheritability of military skills or any other innate attribute, such as brains, that sheds glamor on nobility and royalty.

Land and money can indeed be inherited, and the prototypical aristocrat, relieved of the common lot of having to earn his keep, is admired for his opportunity to be a super-educated consumer who, unlike the self-made types we are supposed to admire, is trained from birth in the refinement of manners and taste.

Lacey questions whether inheritance taxes will therefore succeed in destroying aristocracy, and concludes that "snobbery" will at least keep its forms alive. Having previously written "Majesty," "Kingdom" and "Princess," he's not going to be caught following "Aristocrats" with a prettily illustrated volume called "Serfs." No matter how much history and irony he employs, his premise and justification is that these people are privy to a different way of life than the merely rich.

But he fails to gauge what effect the new aristocratic eagerness to participate in such exposure will have on its survival. Books like this help destroy the interest on which they depend.

Aristocracy made the transition from military leadership to landlordship, and some of its members are moving successfully into manufacturing. Indeed, the myth that nobility was, until recent years, unsullied by "trade" is easily exposed; Lacey's examples of aristocrats mostly turn out to be the descendants not of military or political leaders, but of postmen, real estate speculators, money lenders and other humbly useful royal servants.

But how will nobility fare in a publicity-based economy?

Lacey's subjects have all shown themselves eager to cooperate in opening their lives to public scrutiny. His six subjects (the Grosvenors of England, the Frescobaldi of Italy, the Thurn und Taxis of Germany, the Medinaceli of Spain, the Ganays of France and the Liechtensteins who rule that country) all participated in a related BBC television series and are more often self-promoters than victims in the popular press.

This could be their undoing. Aristocratic reputations thrive on scandal, eccentricity and outrage; what threatens them is ordinariness.

The concept of nobility is enhanced when we read, in "Aristocrats," that the Duke of Marlborough, having lost to the war effort the services of a valet whose duties included placing toothpaste on the ducal toothbrush, emerged from his bathroom roaring, "What's the matter with my toothbrush? The damned thing won't foam any more!"

But it is diminished when we read in Vanity Fair that the Duchess of Westminister (of the Grosvenor family) is fretting because she can't get the princess of Wales to return her telephone calls.

Whatever hopes of survival modern nobility may have, we don't need them to tell us what it is like to be snubbed by those who outrank them.