Johann Strauss's attempt to out-Mozart Mozart may not be the sublime, wise treatise on love he intended, but it is now appreciated all over the world as an elegant, tasteful romp about marital indiscretion among the Viennese gentry. And it has come to epitomize for us the gilded-age Vienna, a time and place nostalgically evoked by Fledermaus's peculiar mix of gay melodies, sardonic wit, and gentle irony. The menagerie of characters it introduces to us are, of course, unforgettable: the sweet Rosalinda and her debonair husband Eisenstein, and the world-weary androgyne Count Orlofsky. This is the kind of material on which the Evanston-based Light Opera Works has built its considerable local reputation. I look forward to its new production of the Waltz King's greatest hit, which boasts a capable cast (headed by Catherine Caccavallo and Ruth Williams alternating as Rosalinda), a knowledgeable music director, (Alan Heatherington), and staging by a prize-winning choreographer (Peter Amster). Tuesday, December 30, 2 PM; Wednesday, December 31, and Friday and Saturday, January 2 and 3, 8 PM; and Sunday, January 4, 2 PM; Cahn Auditorium, Northwestern University, 600 Emerson, Evanston; 869-6300.