Part 1. Understanding astronomy. Discovering the night sky. Gravitation and the motion of the planets. Light and telescopes. Atomic physics and spectra -- Part 2. Understanding the solar system. Formation of the solar system and other planetary systems. Earth and moon. The other terrestrial planets. The outer planets. Vagabonds of the solar system. The sun: Our extradordinary ordinary star -- Part 3. Understanding the stars. Characterizing the stars. The lives of stars from birth through middle age. The death of stars. Black holes: Matters of gravity -- Part 4. Understanding the universe. The Milkly Way Galaxy. Galaxies. Quasars and other active galaxies. Cosmology. Astrobiology.