Yambo, the cerebral 59-year-old narrator of Umberto Eco's dreamy new opus, The Mysterious Flame of Queen Loana, awakens in a Milanese hospital unable to recognize his wife, but still capable of quoting from Moby-Dick. His mind has become, as he puts it, ''a maelstrom of memories that were not mine.'' To reclaim his personal past, Yambo returns to his ancestral country home and begins digging through a moldering collection of family memorabilia, from comic books and news clippings to fascist propaganda and childhood school assignments. Eco takes his time, letting Yambo describe and analyze each piece of ephemera (some of which are reproduced in the pages of the novel). And just when you've decided the book is a beautiful, pointless trip down someone else's memory lane, Eco throws in a sad love story and a haunting World War II adventure, and you realize that the strange journey was well worth taking after all.