In presenting the basics of solar heating and hot water systems, this publication is organized from the general to the specific. It begins by presenting functional and operational descriptions of solar heating and domestic hot water systems, outlining the basic concepts and terminology. This is followed by a description of solar energy utilization that traces the principles of solar energy from climate to radiation gain to solar collection. Finally, the manner in which solar components can be organized into solar heating and hot water systems is discussed including: collector-storage arrangements, storage distribution arrangements, domestic hot water preheating types, and specific system components. (Author/BB)