The approach of this book is to defend a theory of well-being that solves a particular practical problem, namely, the problem of how to help others, particularly our friends, attain greater well-being. This introductory chapter sets out this problem, explains why it is a problem, provides some illustrative examples, and introduces the value fulfillment theory as a solution to the problem. The final section of the chapter compares the value fulfillment theory to other theories in philosophy and psychology (hedonism, life satisfaction theory, desire satisfactionism, eudaimonism, objective list theory). The aim here is not to prove the other theories are wrong, but to make space for the value fulfillment alternative.