From a security standpoint, things don't get much worse than the opening scene of Lee Dodson's Infiltration. The book's protagonist, a 67-year-old rancher named Rand (picture a cross between Tommy Lee Jones in "No Country for Old Men" and Sly Stallone in "Rambo"), is awakened in his home in the middle of the night by the subtle but unmistakable sound of a silenced gunshot.What gradually unfolds is that the infiltrators--a combined force of Mexican...