Book excerpt: In Leviathan Thomas Hobbes defines moral philosophy as 'the science of Virtue and Vice', yet few modern readers take this description seriously. Moreover, it is typically assumed that Hobbes' ethical views are unrelated to his views of science. Influential modern interpreters have portrayed Hobbes as either an amoralist, or a moral contractarian, or a rule egoist, or a divine command theorist. David Boonin-Vail challenges all these assumptions and presents a new, and very unorthodox, interpretation of Hobbes's ethics. He shows that Hobbes is best understood as embracing a theory of virtue concerned with the development of good character traits rather than with rules of behaviour. In focusing in a quite new way on Hobbes's moral theory this book is likely to attract considerable attention amongst both philosophers and intellectual historians.