This book traces the progress of planetary science and highlights some of its key concepts and applications. Celestial bodies like planets, moons, gas giants, micrometeoroids, etc. are extensively studied under planetary science. It also involves the study of planetary systems like the solar system. Over the years, this field has evolved from astronomy and earth science to form several other sub-fields like planetary geology, atmospheric science, exoplanetology, etc. This text strives to provide a fair idea about this discipline and to help develop a good understanding of planetary science and its related fields. The various studies that are constantly contributing towards advancing technologies and evolution of planetary science are examined in detail. Those in search of information to further their knowledge will be greatly assisted by this book. It will help the readers in keeping pace with the rapid changes in this field.