Cross My Heart by James Patterson

Cross My Heart (Alex Cross) -  The novel opens with Alex Cross roaming the streets of DC, mourning the loss of his family.  Two weeks earlier, Marcus Sunday, author of The Perfect Criminal, lectures on his theories.  He contends that the perfect criminal believes that life is "meaningless and valueless." He also claims that the perfect detective, one who believes in the moral and ethical world, is the "antithesis of the perfect criminal."  Furthermore, Sunday claims that the perfect detective can be made to see the meaningless of life and so become the perfect criminal.  To prove his point, Sunday stalks Alex Cross' family with the intent to ruin Cross and thus prove his point.