In the dying light of the nineteenth century, the world came to know and fear terrorism. Like today, this was a time of progress and dread, characterised by political and technological breakthroughs and waves of immigration that swelled the populations of ever-expanding cities. The era also simmered with political rage and social inequalities, which drove nationalists, nihilists, anarchists and republicans to dynamite cities and gun down presidents, police chiefs and emperors. This wave of terror was seized upon by an outrage-hungry press that peddled hysteria, conspiracy theories and fake news in response, convincing many that they were living through the end of days. The rise of devils chronicles the journeys of those who provoked this panic and created modern terrorism - revolutionary philosophers, cult leaders, criminals and charlatans, as well as the paranoid police chiefs and unscrupulous spies who tried to thwart them. In doing so, the book explains how radicals once thought just in their causes became, in the words of Pope Pius IX, 'devils risen up from Hell'.