Cool Stars 14 - Submitted Abstract # 164 This version created on 05 October 2006 Theory, Synthesis, and Future Directions Donald Terndrup, Ohio State University During the last decade we have seen a remarkable interplay of theory and observations, leading to many successes in helioseismology and the understanding of the evolution of young stars. Future developments, especially large parallax surveys, will permit us to investigate many other types of stars with equal accuracy. After a review of the sensitivity of stellar models to the treatment of convection, element separation processes, and detailed abundance patterns, I will discuss figures of merit which must be achieved in order to make further progress. I will show that it is particularly important to determine highly accurate temperatures and metallicities over wide swaths of the H-R diagram. ----------------------------------