In the 21st century, disengaging, even briefly, is seen by many as self-indulgent, unproductive, and antisocial. Yet to retreat is as basic a human need as being social, and everyone can benefit, whether it's for a weekend, a month, or a lifetime. Retreat is an uncertain adventure with as many peaks and valleys as any mountain expedition, except we head inward, to recharge and find fresh energy and brave new ideas to bring back into our everyday lives.