This volume describes the techniques with which astronomers and astrophysicists seek out worlds similar to our native planet throughout the vastness of the universe. Breaking down sometimes complicated concepts for beginning students of the cosmos, it includes the history of this planetary quest from ancient to modern times, contemporary methods used to find exoplanets, and their sheer diversity. Altogether, this otherworldly exploration, visually rich with the imagery of the heavens, gives readers a great entry point into a branch of astronomy that has thrilled inquisitive minds for millennia.