“In our current era of non-stop technological innovation, fuzzy wishful thinking has yielded to the hard doctrine of personal optimization. Self-help gurus need not be charlatans peddling snake oil. Many are psychologists with impressive academic pedigrees and a commitment to scientific methodologies, or tech entrepreneurs with enviable records of success in life and business. What they’re selling is metrics. It’s no longer enough to imagine our way to a better state of body or mind. We must now chart our progress, count our steps, log our sleep rhythms, tweak our diets, record our negative thoughts—then analyze the data, recalibrate, and repeat.”