Now available in paperback. An introduction to the theory of the interactions of pions and Kaons with atomic nuclei. Emphasis is on scattering of these mesons by nuclei, and the induced reactions, including the absorption or production of mesons. The central method presented is the theory of multiple scattering developed by Watson and others. Also developed are methods that account for absorption and production of mesons, in which meson degrees of freedom are explicitly involved. Other mesons, as secondary particles, are covered in the appropriate contexts. The role of mesons in nuclear dynamics is also addressed. Finally, alternate approaches to scattering theory are considered.