The second in a series of books published with the IZA, this volume presents Richard Easterlin's outstanding research on the analysis of subjective well-being, and on the relationship between demographic developments and economic outcomes. In both fields, his work has laid the foundations for enlarging the scope of traditional economic analysis and has increased our understanding of behaviour in several important domains, such as fertility choices, labour market behaviour, and the determinants of individual well-being. In various seminal contributions, Easterlin has demonstrated the importance of material aspirations and relative economic status for human behaviour. This book is a collection of 11 of his key papers, revised and edited to make a cohesive book. New material includes an Introduction from the editors, two section Introductions from Easterlin, and an Epilogue from Easterlin.