Despite decades of empirical happiness research, there is still little evidence for the positive effect of economic growth on life satisfaction. This poses a major challenge to welfare economic theory and to normative conceptions of socio-economic development. This book endeavours to explain these findings and to make sense of their ethical implications. While most of the existing literature on empirical happiness research is ultimately interested in understanding how to improve human lives and societal development, the ethical backdrop against which these findings are evaluated is rarely made explicit. In contrast to this, Professor Hirata focuses on the role happiness should play in an ethically founded conception of good development. Taking a development ethics perspective, this book proposes a nuanced conception of happiness that includes both its affective and its normative dimensions and embeds this in a comprehensive conception of good development. The argument is that happiness should not be regarded as the only thing that determines a good life and that good development cannot sensibly be thought of as a matter of maximizing happiness. Happiness should rather be seen as an important indicator for the presence or absence of those concerns that really matter to people: the reasons that give rise to happiness. This book should be of interest to students and researchers of economics, psychology and development studies.