A monumental amount of research and development work has been invested in multiphase flow modeling over the past 50 years. Yet, many challenges remain as we incorporate additional phases, account for exotic fluids, and push our simulation tools to their limits in the desire to optimize even more-complex production systems fraught with difficult flow assurance issues. A visual history of the evolution of steady-state multiphase flow models will be presented, leading to the current "state-of-the-art". Looking toward the future, it is important that the models be advanced to address areas of greatest uncertainty and align with trends in field development strategies. The authors' views of the top five areas of reseearch and development (R&D) necessary for these purposes will be presented.