Herr Hapsburg, the taxi is waiting"" . . . and so in November 1918 the last Austro-Hungarian emperor left quietly for exile in Switzerland. Here--briefly told, extensively pictured--are the last glory days and the later lives of the Hohenzollerns, the Hapsburgs, the Romanovs; the short, serio-comic reigns of the Balkan kings (remember Zog?); the adaptable monarchies of Belgium and the Netherlands; and the unceremonious royal houses of Sweden, Denmark, and Norway. Judd, responsible earlier for the House of Windsor (1974), is a straightforward chronicler who acknowledges his subjects' merits and doesn't gloat over their sins. A field day for royalty-watchers and a boon for those curious souls who wonder Where They Are Now.