American editor Robert Cowley has brought together those whom his meaty book dubs "the world's foremost military historians" to describe details of significant human conflicts and to construct plausible "counterfactual" events. The balance between the actual and the speculative varies between essays but the counterfactual is always used as "a tool to enhance the understanding of history".Beginning with the siege of Jerusalem in 701 BC and ending with the Cold War, the contributors posit some amazing historical alternatives. Christianity and Islam, for example, may never have existed and Hitler might have been killed in the First World War. Generally taking a "Western" (sometimes specifically American) perspective, the far-reaching repercussions of real and imagined events are shown. Information gems include the fact that Genghis Khan's soldiers wore silk underwear and that the Kaiser almost met his end in a Wild West show stunt in 1889. What If? reveals that the path of history is a mix of action, reaction and chance. As the editor writes, "milliseconds can influence centuries" and "the difference can be as slight as the path of a bullet". A book of both facts and opinions, it can be argued with as well as learnt from. It might provide perfect fodder for an intellectual dinner party--although pondering the frightening unpredictability of past and future could damage your appetite! --Karen Tiley