When temperatures are low enough, every substance in thermal equilibrium must become ordered. Since some materials remain fluid even to the lowest temperatures, it is fascinating to ask how this ordering can take place. One possibility is the formation of a superfluid state, one in which there is macroscopic quantum order-or what may be called quantum mechanics in a tea-cup. Designed for final-year undergraduates or beginning graduate students, Basic Superfluids begins with these ideas. The author assumes some knowledge of quantum, statistical, and thermal physics, and builds on this background to give a readable introduction to the three superfluids of low temperature physics.