Space weather is an emerging field of space science focused on understanding societal and technological impacts of the solar-terrestrial relationship. The Sun, which has tremendous influence on Earth's space environment, releases vast amounts of energy in the form of electromagnetic and particle radiation that can damage or destroy satellite, navigation, communication and power distribution systems. This textbook introduces the relationship between the Sun and Earth, and shows how it impacts our technological society. One of the first undergraduate textbooks on space weather aimed at non-science majors, it uses the practical aspects of space weather to introduce space physics and give students an understanding of the Sun-Earth relationship. Definitions of important terms are given throughout the text. Key concepts, supplements, and review questions are given at the end of each chapter to help students understand the materials covered. This textbook is ideal for introductory space physics courses.