" Unlike scholarly journals, mass-market advice books are rarely reviewed by experts in the field. Instead of getting tested research findings, most of the time you get what some author claims worked for him or her, or what someone thinks might work for you, or what some publisher’s marketing department hopes you will think might work for you, all mixed in with “time-tested rules” that might have worked in the past but no longer hold true. "

― Stephanie Coontz , Marriage, a History: From Obedience to Intimacy or How Love Conquered Marriage