In the two decades since astronomers first discovered the existence of a planet outside of our solar system, "exoplanetology" has become the hottest specialty in astrophysics. Scientists young and old, inspired by the thought of finding either another habitable world or the Holy Grail of space exploration, life itself, flocked to be part of this burgeoning field. With so much brainpower on hand, it's no wonder that investigative techniques advanced more quickly than anyone would have thought. To date, more than 1,000 exoplanets have been found, and in this eBook, Exoplanets: Worlds Without End, we delve into this quest that sometimes sounds more like science fiction than science. Section 1, "Exo-Search," sets the stage and outlines how astronomers are looking for new worlds: the various techniques, how they've improved to date and plans for upcoming missions. Sections 2 through 5 analyze the discoveries, often both controversial and strange. Section 3 focuses on the race to find other Earth-like planets. With excitement at an all-time high, author Ron Cowen cautions against publishing too quickly out of optimism. In "Noisy Stars May Create Phantom Planets," Cowen describes how stellar activity can mimic the signs of tiny exoplanets. Section 4 takes on the real oddballs. They may be remnants of gas giants whose atmospheres were stripped away, as in the piece "The Bones of Giants," or have alien chemistries. Some trace their course around white dwarfs, the results of a second generation of planets forming around old stars. Section 5 asks if there's life out there. In "Anybody Home?" John Matson describes the search for the chemical signatures that scientists think are telltale signs that we're not the only living things in this part of the universe. So far, we're still alone out here, but in a field where the discoveries are coming thick and fast, it's exciting to think that it could all change tomorrow.