This paper presents and discusses the contents of two books edited by Luigino Bruni and Pier Luigi Porta (2004 and 2006) on the evolution of self-reported happiness in developed economies and its interrelations with economic growth and citizen's freedom. The author summarizes the main determinants of happiness according to the recent empirical literature as discussed in the chapters assembled by the editors of the books here reviewed. None of these factors is sufficient by itself to explain the "paradox of happiness", that is the decoupling between the trends of self-reported happiness and of income per head. However, when we consider them together, the paradox disappears. The actual paradox is the persistent use of the PIL statistics to measure the well-being (or happiness) of citizen's notwithstanding well-known shortcomings further clarified and emphasized by the literature here reviewed.