The spin foam framework provides a way to define the dynamics of canonical loop quantum gravity in a spacetime covariant way, by using a path integral over histories of quantum states which can be interpreted as `quantum space-times'. This chapter provides a basic introduction to spin foams aimed principally at beginning graduate students and, where possible, at broader audiences.

32 pages, 14 figures, 2 tables, to appear as a chapter of "The Springer Handbook of Spacetime," edited by A. Ashtekar and V. Petkov (Springer-Verlag, at Press)