Book excerpt: Ancient Rome, in this accurate and evocative series, is just as politics driven as any major American city -- possibly even more. Decius Caecilius Metellus has, through a series of rather wild adventure, and in the act of tracking down killers and other reprobates, barely escaped annhilation several times. Now, newly elected to the office of aedile, the lowest rung on the ladder of Roman authority, he must smoke out corruption and conspiracy that threaten to destroy all of Rome.