1 The Electromagnetic Program for the Synthesis of Physics.- 2 The General Theory of Relativity: The Core of the Program of Unified Field Theories.- 3 Weyl's Theory: The First Truly Geometrized Unified Field Theory.- 4 1921: The Pivotal Year of Unified Geometrized Field Theories.- 5 Einstein's Decade of Hopes and Disappointments.- 6 The Role of Unified Geometrized Field Theories in the Genesis and Development of Quantum Theory.- Concluding Remarks...