This Research Handbook offers a comprehensive and state-of-the-art collection on the competition law (antitrust) prohibition of abuse of a dominant position and monopolization. It draws from the long and influential traditions of leading jurisdictions such as the European Union and the United States to analyse applicable rules and policy in these jurisdictions. It also takes a comparative approach to identify common threads and differences. Bringing together contributions from authoritative legal and economic experts, it provides an in-depth analysis of foundational legal and economic principles which guide the Research Handbook’s exploration of the concept and prohibition of abuse of a dominant position. With comprehensive breadth, an interdisciplinary approach, and trans-Atlantic coverage, this Research Handbook covers various important topics including market definition and market power, different types of abuse, enforcement, cross-cutting issues such as mandated neutrality, big data and the interface of competition and regulation. The blend of theoretical study and practical advice on the topic will make this a vital resource for scholars and advanced students wanting a rounded appreciation of this area of the law, whilst practitioners, competition officials, and policymakers will also find this a beneficial companion.