Chapter 1 introduces the book’s argument. Naming Ukraine’s war is controversial. Russia quickly appropriated the term “civil war,” cynically in order to claim noninvolvement. This flies in the face of evidence. The social science literature on civil war violence and barriers to settlements may be analytically useful, however, for understanding why the conflict in Ukraine was so difficult to bring to resolution in the 2015–2022 period. This book explains that Russia, after seizing Crimea, was reacting to events it could not control and sent troops only to areas of Ukraine where it knew it would face little resistance (the Eastern Donbas). Kremlin decision-makers misunderstood the attachment of the Russian-speaking population to the Ukrainian state and also failed to anticipate how that their intervention would transform Ukraine into a more cohesively “Ukrainian” polity.