21 Lessons for the 21st Century - Yuval Noah Harari

Terrorists undertake an impossible mission: to change the political balance of power through violence, despite having no army. To achieve their aim, terrorists present the state with an impossible challenge of their own: to prove that it can protect all its citizens from political violence, anywhere, any time. The terrorists hope that when the state tries to fulfil this impossible mission, it will reshuffle the political cards, and hand them some unforeseen ace.