This book by Hristos Doucouliagos, Richard Freeman and Patrice Laroche provides an in-depth and impressively executed meta-analytic investigation and synthesis of the econometric evidence produced on the economic effects of trade unions since publication of the landmark volume What Do Unions Do? (WDUD) in 1984 by Freeman and Medoff. For Freeman, the book is a fitting tribute to one of the most famous and enduring works ever written on unions and, similarly, for Doucouliagos, Laroche and their colleague Stanley, it is a fitting tribute to their pioneering work on use of meta-analysis in labour economics. One of the standout innovations of WDUD (1984) was to broaden econometric analysis of unions beyond the traditional topic of wage effects to include a variety of non-wage outcomes, such as productivity level and growth, capital investment, employee turnover, job satisfaction and firm profitability. This broader palette of union effects was inspired, in turn, by Freeman and Medoff’s equally innovative expansion of the traditional monopoly model of union wage effects to include collective voice and institutional response effects.