Explore the concept of solar systems beyond our own in this final lecture of Carl Sagan's 1977 Christmas Lectures series. Delve into theoretical work suggesting planets frequently accompany stars, and consider the implications for potential extraterrestrial life. Examine the state of planetary discovery at the time, contrasting it with modern findings of over 450 exoplanets. Learn about the evolution of planetary exploration, from early interpretations of Mars to NASA's Viking Program. Discover the origins and significance of the Royal Institution Christmas Lectures, a long-standing tradition of presenting science to young people. Investigate topics such as the neighborhood of the Sun, perspective of stars, future space exploration, the Voyager phonograph record, evolution of Earth, radio astronomy, natural frequencies, and the possibility of extraterrestrial contact.