Drawing masterfully on 500 years of international history, Owen reminds readers that the use of military force to change, construct, or preserve foreign regimes is hardly a new phenomenon. By his count, there have been 209 such attempts since 1500. A majority of these had an ideological agenda. Between 1510 and 1700, Catholic and Protestant rulers in central and western Europe used force to aid coreligionists in other countries. Efforts to spread republican regimes, constitutional monarchies, and absolute monarchies were common in Europe and the Americas between 1770 and 1870, whereas most regime-promotion attempts in the twentieth century sought to defend or defeat communism, liberalism, or fascism. Another such struggle continues today in the Muslim world, with secularism arrayed against Islamism. Owen explains that in periods of intensified ideological contestation, rulers have generally believed that "birds of a feather" lend one another legitimacy and adopt more consonant foreign policies. He also argues that forcible regime promotion has been an opportunistic strategic weapon -- directed chiefly at unstable or defeated states -- rather than a principled end in itself. The practice, moreover, reinforces the perception that alien ideologies are monolithic and dangerous, creating vicious circles of polarization and interventionism. The historical narratives Owen employs to test this theory are nuanced, illuminating, and a joy to read.