Though the present work focuses on optical extinction and transmission, MPM can be extended to address related properties of interest. One example is treating circularly polarized electric fields, enabling simulation and design of plasmonic materials with chiroptical responses. Here we have established MPM's ability to quantify many-body contributions to the optical response of complex assemblies, treated at the level of dipoles. This approach explicitly incorporates structural complexity, explaining and predicting optical phenomena that cannot be captured in effective medium and mean field theories. Though many-bodied dipoles are sufficient to describe most observations of nanoparticle assemblies, it is possible, though increasingly computationally intensive, to make MPM more quantitatively predictive by systematically including higher-order polarization moments (quadrupoles, etc.) in the analysis. Finally, strategies for treating nonspherical nanoparticles have been developed as extensions to Mie theory, and similar approaches may be pursued to extend MPM to handle triaxial ellipsoids or cubes.