The Grossman model is the canonical theory of the demand for health and health investment. This paper provides strong support for the model’s canonical status. Yet several authors have identiﬁed at least four signiﬁcant limitations to the literature spawned by Grossman’s seminal 1972 papers. I show that these criticisms are not the result of a ﬂawed model but of an unfortunate and unnecessary choice for the functional form (linear in investment) of the health-production process, and of an incorrect interpretation of the equilibrium condition for health. I ﬁnd that a generalized Grossman model, with decreasing returns in investment and endogenous longevity, addresses the limitations, and provides a remarkably successful foundation for understanding decisions regarding health.