Books, apps, coaching sessions: Today, happiness is everywhere. We might think that there is nothing wrong with this common-sense concern. But it’s actually the opposite of social reality. So what lies behind this contemporary obsession with happiness and the billions of euros generated by its industry? Philosophers, sociologists, economists and psychiatrists including Christophe André, Éva Illouz, Martin Seligman and Julia De Funès, confront their point of view and decipher one of the most captivating and worrying phenomena of this early century.