Blood and Concrete: 21st Century Conflict in Urban Centers and Megacities provides a foundation for understanding urban operations and sustaining urban warfare research. This Small Wars Journal (SWJ) Anthology documents over a decade of writings on urban conflict. In addition to essays originally published at SWJ, it adds new content, including an introduction by the editors, a preface, “Blood and Concrete,” by David Kilcullen, a foreword, “Urban Warfare Studies,” by John Spencer, a postscript, “Cities in the Crossfire: The Rise of Urban Violence,” by Margarita Konaev, and an afterword, “Urban Operations: Meeting Challenges, Seizing Opportunities, Improving the Approach,” by Russell W. Glenn. These essays frame the discussion found in the collection’s remaining forty-nine chapters. Blood and Concrete continues the legacy of Small Wars Journal’s coverage of urban operations, conflict, and combat.