Matthew Woodring Stover, BLADE OF TYSHALLEMatthew Wood. , $16 (736pp) ISBN 978-0-345-42144-9

A host of action sequences (whose detailed choreography reflects the author's martial-arts background), subplots, counterplots and secondary characters (some gruesome enough to give Hannibal Lecter pause) extend (some will feel pad) Stover's (Heroes Die, etc.) latest epic. A century or more from now, Earth's 14 billion people are kept under control not only by a rigidly hierarchical totalitarianism but by the entertainment provided by the adventures in the Overworld, a parallel world that seems to be the Faerie of myth and folklore. Hari Michaelson, a media executive on Earth but a formidable assassin named Caine in the Overworld, discovers a monstrous plot to infect Overworld with a deadly virus and depopulate it for the benefit of Earth's oligarchy. With the help of his wife, Shanna, in her avatar as the goddess Pallas Ril, and his old fighting instructor Kris Hansen, now an Overworld mage named Deliann, Caine/Michaelson fights a long and involved battle against both the Earth conspiracy and Overworld's dark god Ma'elKoth. How it all turns out matters a lot less than the immediate, often X-rated action. In spite of its high ambitions and a considerable level of intelligence, the book goes over the edge from complex into convoluted, and among efforts to combine SF and fantasy (consider Tad Williams's Otherland series and classic Michael Moorcock) has to be ranked as an interesting near miss. (Mar.)