This lecture by Prof. William A. Curtin covers the multiscale mechanics of metal plasticity, focusing on the challenges and performance dependencies from atomic to millimeter scales. Topics include dislocations, crystal plasticity, and atomistic plasticity, with a detailed explanation of the information-passing paradigm in multiscale modeling. The lecture also delves into the physics of plasticity, dynamic strain aging in aluminum alloys, and the development of constitutive flow rules for materials like aluminum and steel.