The interdisciplinary studies included in the special issue of the Psychiatrische Praxis "On Happiness" tackle that topic from various, diverse directions. It is the aim of this concluding contribution to provide some orientation from a philosophical perspective, sketching themes and problems that one might encounter in an investigation of happiness. The survey is guided by four fundamental questions: What is happiness? How to become happy? How important is it to be happy? And how is happiness related to ethics?