This chapter aims to make plausible that there is at least one other domain of rationality yet to be discussed: hedonic rationality. Hedonic rationality is concerned with the rationality of the hedonics. Emotions and emotional episodes are complex and no proponent of the rationality of the emotions argue for the rationality of affect, or hedonics, as such—instead, they focus on some other feature or combination of features. The chapter describes the proposed hedonic rationality from the rationality of the emotions and addresses methodological problems determining whether any mental phenomenon is rational and outlines the ecumenical approach. The rationality or irrationality of affective states will have to be generally reconsidered if it turns out that hedonic tone is itself rationally assessable. Identifying a hedonic aim that explains the evaluative practices requires empirical inquiry into what negative hedonic tone, and hedonic tone more generally, does.