Yugoslavian writer Pavi (Dictionary of the Khazars, 1988; Landscape Painted With Tea, 1990) loves to twin his metaphors, tropes, and conceits. Here, he does so with the story of Hero and Leander--given form in Leander's case by an 18th-century architect who knows that his fate lies in a beheading; and, in Hero's, by the story of a Czech woman in the 1930's who finds herself unable to live in, or even understand, the present tense. Pavi tells the two stories in parallel, bound in opposite directions inside the actual book: you flip over the book when you finish one half in order to read the other. Time, space, sex, death--everything here is a corollary, with a corresponding double--and either you're charmed by the strenuous artifice or you're not. To be had are philosophical and linguistic aperáus almost worth the price of admission (such as dreams considered ``like something as yet unexperienced, like some strange tomorrow that has started ahead of time, like an advance loan taken on future life, the future that is realized after the dreamer [enclosed in the future tense] has avoided the inevitable now''), but the packaging and the whimsy don't ever make the concept stand up quite straight enough. Slight.