Thousands of exoplanets are known to orbit nearby stars and small rocky planets are established to be common. The ambitious goal of identifying a habitable or inhabited world is within reach. But how likely are we to succeed? The race to find habitable exoplanets has accelerated with the realization that “big Earths” transiting small stars can be both discovered and characterized with current technology. While future generations may use very large space-based telescopes to search to find signs of life amidst a yet unknown range of planetary environments, what will it take to identify such habitable worlds with the observations and theoretical tools available to us?