A building that hums at night hears things differently than the people who walk its halls by day. I've been sitting with the Lewis-edited *Cambridge Companion* again, and what strikes me ten years on is not what the contributors got wrong — most edited volumes in this space age poorly — but the particular shape of the silence around what they couldn't yet see. In 2016, the book's central intervention felt bold enough: resist the temptation to reduce religious terrorism to either pure theology or pure material grievance. The truth, the volume argued, lives in the interaction. That thesis has held up remarkably well. What hasn't held up is the implicit geography of the argument — the unstated assumption that the primary analytical challenge was understanding *them*, over *there*, radicalizing in ways legible to Western security frameworks. The book's diverse case studies and its insistence on theoretical pluralism were genuine strengths. But the pluralism was methodological, not always perspectival. The voices doing the analyzing remained, with few exceptions, situated in the same institutional corridors.

What the volume did anticipate, sometimes with uncomfortable clarity, was the mechanics of radicalization as a process rather than an event — the slow accumulation of grievance, identity foreclosure, and meaning-making that could attach itself to almost any doctrinal framework. This insight, which several contributors developed with care, turned out to be more universally applicable than the book's own framing suggested. By 2020, the same radicalization pipelines the volume described in the context of jihadist movements were visibly operating in QAnon networks, accelerationist white supremacist cells, and hybrid religious-nationalist movements from India to Brazil to the United States. The contributors who emphasized the sociological infrastructure of radicalization over its theological content were, in hindsight, building tools that outlasted their own case studies. Those who leaned harder on doctrinal exegesis — trying to locate violence in specific textual traditions — now read as artifacts of a moment when the field still believed you could quarantine the problem inside particular religions.

The most conspicuous absence is technological. Published in 2016, the volume arrived just before the full algorithmic weaponization of social media became undeniable. There is no sustained engagement with platform architecture as a radicalizing force, no reckoning with the way recommendation engines could do the work that charismatic clerics once did. By 2024, we had watched generative AI produce bespoke propaganda at scale, deepfake religious authorities issue fabricated fatwas, and encrypted channels become the new madrasas — decentralized, borderless, optimized for engagement rather than coherence. The book treats media as a distribution channel. It was already becoming the seminary. Likewise absent is any serious treatment of state-sponsored religious terrorism as a category — the ways governments in Myanmar, India, China, and elsewhere would instrumentalize religious identity not as a deviation from state power but as its extension. The volume's implicit model still assumed terrorism as a challenge *to* the state. The decade since has made clear it is often a function *of* the state.