State survival plays a key role in international relations theory. Lemke casts a wider net than in previous research on state death and also considers contenders that control territory without external recognition (such as Somaliland) or rebels that can deny the government access to territory. This allows for studying more actors at risk of death as well as comparing contenders and states that achieve external recognition. Using new detailed data on territorial contenders since 1810, Lemke shows how they differ from states, but many propositions about state emergence and death also apply to contenders. This includes arguments about how conflict often strengthens states and how defeat increases the risk of death. The sovereignty norm after 1945 appears to lower date rates for territorial contenders more than for sovereign states. The findings are more consistent with English school ideas of a rule-based international society than with realism. The book makes a persuasive case for the value of collecting data on a broader set of state deaths and for international relations as the study of how they interact. Lemke’s notion of state death is unconventional and includes cases where a territorial contender replaces a government. This may be reasonable, but raises the question whether regime change by a nonterritorial contender could be regarded as a form of state death or replacement. Expanding actors beyond conventional definitions of states brings in new challenges, but Lemke’s book shows the payoff from challenging conventions. It also inspires new avenues for research and demonstrates the value of actually collecting new data over relying on assumptions about implications.