"Much of the current intense study of molecular conduction junctions is motivated by their possible technological applications, however this research focuses on fundamental questions associated with the properties and operation of such systems. Junctions based on redox molecules often show non-linear conduction behavior as function of imposed bias. Optical interactions in molecular junctions pertain to junction characterization and control. Issues of heating and thermal stability require a proper definition of thermal states (effective temperature) and the understanding of heat production and thermal conduction in non-equilibrium junctions. This proposal focuses on theoretical problems pertaining to these phenomena with the following goals: (a) Develop theoretical methodologies for treating non-equilibrium molecular systems under the combined driving of electrical bias, thermal gradients and optical fields; (b) provide theoretical tools needed for the understanding and interpretation of new and ongoing experimental efforts involving thermal, optical and redox (charging) phenomena in molecular junctions, and (c) use the acquired insight to suggest new methods for characterization, functionality, control and stability of molecular junctions."