This volume contains the proceedings of an International Conference on "Spin and Isospin in Nuclear Interactions," which was held in Telluride, Colorado USA, 11-15 March 1991. This was the fifth in a series of conferences held in Telluride every three years since 1979. In attendance at the conference were just under 100 participants, representing a total of 43 institutes from 12 different countries. In keeping with previous Telluride conferences, the role of spin and isospin degrees of freedom in both nuclear structure and nuclear interactions remained an important theme. Topics covered included new results on the spin- and isospin-dependent terms in the free and effective nucleon-nucleon interaction, Gamow-Teller excitations, charge and spin exchange with hadronic probes, and spin measurements with leptonic probes. Recent progress in the development of polarized sources, polarized targets, and po larimetry was also discussed, as were applications to neutrino physics and astrophysics. Whereas earlier Telluride conferences had dealt primarily with nucleon-nucleus inter actions, this meeting included extensive discussions on the role of spin and flavor in particle interactions, and on ways of "bridging the gap" between concepts usually as sociated with particle physics and the domain of more conventional nuclear physics. The conference consisted of morning and evening scientific sessions, leaving the afternoons free for informal discussions, recreation, and enjoyment of the scenic beauty of the Telluride area. In addition to the invited talks, time was allotted for contributed talks on new results."