Garfield's approach to the Hanoverians, via a chronological tour of London's National Portrait Gallery, is a highbrow one, delightfully full of donnish acerbity and lyrical enthusiasms but also so allusive that unversed readers may lose the thread of fact altogether. Garfield begins his tour of faces with the Plantagenets and when we do encounter the Hanoverians here they are not the Georges, who appear only briefly and incidentally, but the intellectual giants--Hogarth, Handel, Johnson, and Fielding. Their genius provides Garfield with an occasion to bring to task others he finds wanting, especially Joshua Reynolds and Lawrence Sterne, to muse on the transition from aristocratic to bourgeois art, and to engage in verbal sparring with a museum attendant who warns that ""by the time you've brought us all (the lower classes) into the light, you'll have cleared away all the things we were looking forward to seeing."" The portraits themselves are copiously reproduced, but often awkwardly placed, pages away from references in the text, and can be confusing, as when Handel's ""blue velvet"" suit shows up brown in one full-color plate. On the whole, Garfield's essay is an irreverently literate and wittily personalized commentary on the period, though it assumes a familiarity with English rulers and styles, not to mention an ingrained attitude to class differences that could leave the average American young person in the dark.