Are we the only sentient beings in the universe? What is the likelihood that others exist in the cosmos? Can they visit us? Can we communicate with them? Where are they? This seminar examines the last fifty years of the scientific search for intelligent life off the earth. The occurrence of intelligence on a planet depends on astrophysical, biological, and environmental factors. This course investigates these factors in an attempt to estimate the number of civilizations within our galaxy. The class also examines the pessimistic view that we are truly the only intelligent life in the galaxy based on the lack of extraterrestrial artifacts within the solar system. In order to gain an appreciation of the main instrument used in SETI, the class constructs and use a simple radio telescope.