Identical twins have been the storyteller's friend since Roman times. Master-scribbler Ken Follett does the arrangement one better in his latest yarn, The Third Twin. The heroine, Jeannie Ferrami, is a young professor at Jones Falls University (JFU)(think Johns Hopkins) who is investigating the balance of nature versus nurture in criminality. Driven by a secret from her past, Dr. Ferrami is overjoyed to find that a straight-arrow law student at JFU has an identical twin (raised separately) who is a convicted rapist. She is not overjoyed, however, when that man is arrested for raping her best friend. Surely Mr. Perfect couldn't be guilty--enter the evil masterminds, three Nixon-era compadres who have been toiling for decades to make America safe for racial purity. It's bad enough that one of the conspirators is Dr. Ferrami's boss, but another is eyeing the Oval Office. The young professor has stumbled onto a secret that could ruin them all, and it's only a matter of pages before bad things start to happen to the pair. The shortest distance between two points is a Follett plot. Look elsewhere for subtlety; entertainment, we got.