This book analyzes the entire spectrum of energy, from conventional sources to various alternative sources. Historically, the Sun has been viewed as the ultimate source of energy on the Earth. All forms of energy - fossil fuels and renewables alike - owe their existence to the Sun. The book also provides a historical perspective on energy policy over the years. It explains the fundamentals of energy and all related aspects using clear and straightforward language, and will serve as a reference guide for all stakeholders including policymakers, academics, students and world citizens in general.