This book offers an extensive description of the poem, with special emphasis on its cheerful version of materialism and on its attempt to devise an ethical system that suits such a universe. It surveys major relevant texts form the eighteenth and ninetheenth centuries (Dryden, Diderot, Voltaire, Tennyson, Santayana) and speculates on why Lucretius and the ancient scientific tradition he championed has become marginalised in the twentieth century. It closes with a discussion of what value the poem has for students of science and technology in the new century: what advice it has to offer us about how to go about reinventing our machines and our morality.