Legions of self-help authors rightly urge personal development as the key to happiness, but they typically fail to focus on its most important objective: hardiness. Though that which doesn't kill us can make us stronger, as Nietzsche tells us, few authors today offer any insight into just how to springboard from adversity to strength.

It doesn't just happen automatically, and it takes practice. New scientific research suggests that resilience isn't something with which only a fortunate few of us have been born, but rather something we can all take specific action to develop. To build...