The rational pursuit of happiness requires knowledge of happiness and in particular answers to the following four questions: (1) Is greater happiness realistically possible? (2) If so, to what extent is that in our own hands? (3) How can we get happier? What things should be considered in the choices we make? (4) How does The pursuit of happiness fit with other things we value? Answers to these questions are not only sought by individuals who want to improve their personal life, they are also on the mind of managers concerned about the happiness of members of their organization and of governments aiming to promote greater happiness of a greater number of citizens. All these actors might make more informed choices if they could draw on a sound base of evidence. In this paper I take stock of the available evidence and the answers it holds for the four types of questions asked by the three kinds of actors. To do this, I use a large collection of research findings on happiness gathered in the World Database of Happiness, which serves as an online supplement to this paper. The data provide good answers to the questions 1 and 2, but fall short on the questions 3 and 4. Priorities for further research are indicated.