This book offers the first comprehensive critical study of David Hume's Four Dissertations of 1757, containing the Natural History of Religion, the Dissertation on the Passions, and the two essays Of Tragedy and Of the Standard of Taste. The author defends two important claims. The first is that these four works were not published together merely for convenience, but that they form a tightly integrated set, unified by the subject matter of the passions. The second is that the theory of the passions they jointly present is significantly different—indeed, significantly improved—from that of the earlier Treatise. Most strikingly, it is anti-egoist and anti-hedonist about motivation, where the Treatise had espoused a Lockean hedonism and egoism. It is also more cognitivist in its analysis of the passions themselves, and demonstrates a greater awareness of the limits of sympathy and of the varieties of human taste. This book is an important contribution to the scholarly literature on Hume's work on the passions, art, and superstitious belief.