Stamping Butterflies

Grimwood stumbles in this ambitious SF stand-alone, which falls short of the high mark set by his Arabesk trilogy (Pashazade , etc.), hard-boiled mysteries set in a near-future where the Ottoman Empire still exists. Grimwood alternates between the present-day efforts of an assassin to kill the U.S. president and a more cryptic future story line set aboard a Chinese spaceship. While the two plots eventually converge in a way most time-travel fans will have anticipated, the whole proves to be less than the sum of its parts. The action can become confusing and the language overblown. As usual, though, the author displays much cunning and wit as he grapples seriously with political themes. (Sept.)