The WFIRST Preparatory Science (WPS) programs support efforts to bridge from basic theory to observational modeling for an implementation of NASA's WFIRST mission. The goal of the WPS initiative is to engage a broad section of the astronomical community into working on the science of WFIRST. Selected WPS science investigations will (1) be directly relevant to WFIRST's primary astrophysics goals, and (2) consist predominantly of WFIRST-specific development of detailed simulations and models. Abstracts of the accepted WPS programs can be found at the GSFC WFIRST site.