Our proposed research program is directed towards developing a better understanding of the quark structure of protons, neutronsand light nuclei. Particular emphasis is placed on measurements of electromagnetic and weak properties of the nucleon using electron scattering at Jefferson Laboratory and MIT-Bates. Such data provide precise information about the spatial distribution of charge and magnetization in the nucleon. A major component of our program is the G0 experiment at Jefferson Laboratory, in which parity violation in polarized electron scattering from hydrogen and deuterium is used to identify the contribution of strange quark-antiquark pairs to the proton's charge and magnetic moment. Coupled to this activity is the determination of "anapole" contributions to proton structure, which arise from parity-violating electromagnetic effects. Also proposed are studies of nucleon excitations using polarization measurements of the recoiling nucleon, and the use of kaon electroproduction to create hypernuclei in which one nucleon in a nuclear system is replaced by a lambda particle.