In this talk I will review recent developments in understanding and controlling light-matter interaction and material response associated with laser powder bed fusion additive manufacturing. As part of the critical assessment of the physics of the process, validated hydrodynamic finite element model simulations have proven to be extremely valuable and can be used to inform rapid solidification microstructural models. I will also discuss new approaches to process optimization that have emerged from our modeling efforts, including laser beam shaping, which can improve material properties and part performance. A brief overview of R&D activities in the Materials Science Division will also be presented. Prepared by LLNL under Contract DE-AC52-07NA27344.