The present well-established study of planets orbiting stars other than our Sun, the exoplanets, was reviewed by the author in his earlier book Wandering Stars. This new and exciting field of study has expanded quickly, particularly due to technological advances in both Earth-based telescopes and, more recently, in the application of automatic space vehicles. Well over 300 exoplanets have now been catalogued, each of mass comparable to or greater than those of the major planets of the Solar System.