This book on statistics of cooperatives is a joint initiative of the International Labour Office (ILO), Committee for the Promotion and Advancement of Cooperatives (COPAC) and the International Centre of Research and Information on Public, Social and Cooperative Economy (CIRIEC). It brings together updated versions of four background studies produced for the ILO and COPAC in the process leading up to the adoption of the Guidelines concerning statistics of cooperatives at the 20th International Conference of Labour Statisticians (ICLS) in October 2018. Together with the guidelines, the book is intended to help statisticians to capture more information on key trends and challenges in the world of cooperatives. This publication is celebrated during the ILO COOP 100 Symposium.