Famous as ferocious warriors, the Ukrainian Cossacks developed their fighting skills in the religious wars against the Tartars, Turks, Poles, and Russians. In this fascinating study, Serhii Plokhy examines the "confessionalization" of religious life in the early modern period, showing how Cossack involvement in the religious struggle between Eastern Orthodoxy and Roman Catholicism helped shape not only Ukrainian but also Russian and Polish cultural identities.