We hear some clichés so frequently that they feel like truths: Progress is undeniable. Count your blessings. You're lucky to be alive here and now. Well, maybe we are and maybe we aren't, argues Christopher Ryan, comparing "progress" to an advancing disease. Prehistoric life was not without serious dangers: A broken bone, infected wound, or difficult pregnancy could be life-threatening. But ultimately, were these threats more murderous than modern scourges? Provocatively, Ryan makes the claim that we should look backwards to find our way into a better future.