Thoroughly updated and re-conceived, Astronomy, Ninth Edition, equips the introductory astronomy student with the essential tools for understanding the cosmos. Michael Zeilik has revised the pedagogy of his successful textbook based on recent research in astronomy education. Significantly shorter than the previous edition, the ninth edition is organized into four concept clusters: Cosmic Distances, Heavenly Motions, Celestial Light and Spectra, and Scientific Models. Material has been streamlined throughout to make the descriptions, concepts, and explanations clearer. Each chapter ends with a concise summary of the concepts in each cluster. Each chapter contains at least one Celestial Navigator, a concept map that provides a visual guide of major concepts in the chapter and explicity shows their connections. Throughout, illustrations have been updated to be clearer and more understandable to the novice student. Michael Zeilik, Professor of Physics and Astronomy and former Presidential Lecturer at the University of New Mexico, specializes in innovative, introductory courses for the novice, non-science major student. In 1998, he was appointed a Research Fellow at the National Institute of Science Education. Zeilik's work has been supported by grants from the National Science Foundation, NASA, the Exxon Educational Foundation, and the Slipher Fund of the National Academy of Sciences. In 1997, the 8th edition of Astronomy: The Evolving Universe won a Texty Award from the Text and Academic Authors Association. In 2002 he was awarded the Astronomy Education Prize by the American Astronomical Society.