In this valuable study of peacekeeping from 1992 to 2014, Hultman, Kathman & Shannon identify the size of a mission as a major factor in the effectiveness of a mission. As a practitioner (former Force Commander and Head of Mission), I find that this book provides a valuable contribution to the discussion in all troop and police contribution countries about what kind of capabilities should be made available for the UN, a discussion that has frequently focused on quality rather than quantity. In addition to a statistical study with new data, case studies of the missions in DRC and Cote d'Ivoire also support the view that size matters. National defence forces have been dramatically reduced in most countries, in part because of the introduction of better and more powerful equipment. Wouldn't this also apply to the UN? Several Force Commanders will claim that peacekeeping forces lack appropriate equipment and training. At a UN Ministerial meeting in London in 2016, the FC from Mali claimed that the death toll could have been halved if the peacekeepers had been better trained and equipped when arriving in the mission area. This book brings new research knowledge which undermines a lot of the experience gained in field missions. However, in the field we know that the uniformed forces are just one of many tools used by the UN; tools that need to work together in a cohesive way to achieve effectiveness and success in a mission. Peacekeeping in the Midst of War provides important research that will hopefully lead to a more comprehensive study of all the elements that are necessary for successful and effective peacekeeping.