Robert Mazo's research program is exclusively theoretical. The general area is statistical mechanics, the science of relating the macroscopic properties of matter to their molecular constitution and to the nature of the forces operating between the molecules. He is interested in both equilibrium and nonequilibrium phenomena. An example of the problems that are examined is the dispersion of particles in N-layer systems. This is a discrete version of the classical phenomenon of Taylor dispersion. Mazo has developed a method of treating the transport properties of particles flowing in a layered system where the velocities in the various layers are different and transitions between the various layers are possible. The model has applications beyond the obvious ones. For example, the problem of the spectrum of an exciton moving along a disordered chain has been treated by the same methods. The techniques use the theory of stochastic processes. Generalizations to more complex situations are being explored.