Experience with electricity markets across the world is more than 30 years long. The time has come to assess the results of the profound overhaul of the industry and explore the challenges that lie ahead in the context of decarbonisation, digitalisation and decentralisation. This e-book provides the reader with a digest of the Handbook on Electricity Markets edited by Jean-Michel Glachant, Paul L. Joskow and Michael G. Pollitt in 2021. The 22 original chapters are summarised and the critical messages made available to a broad audience. The digest, such as the original handbook, covers all dimensions of electricity markets: wholesale and retail; renewable electricity sources; electrification of mobility, heating and cooling; and recent innovations such as distributed generation, electrical energy storage, demand response and digital platforms that are disrupting the industry. The benefits and limits of open markets and competition are assessed at the level of underlying principles and with reference to specific cases, including Great Britain, PJM Interconnection, Texas, Australia, Scandinavia, continental Europe and China. The details of electricity market designs are analysed and discussed. The book also considers new emerging business models and the impact of electricity sector policy priorities such as universal access and deep decarbonisation.