Anthropologist Joshua Brahinsky embarks on an eighteen-year journey into the mind-body practices of charismatic evangelicals-Christians known for their exuberant worship and the enigmatic practice of speaking in tongues. With nearly half a billion followers worldwide, this movement has profoundly shaped both spiritual and political landscapes. What compels believers to return to this practice day after day, year after year? What is it to let go, to fully surrender? What happens in your brain when you get really skilled at release? How does speaking in tongues sit with the new sciences of contemplation and psychedelics? And finally, how does this act of spiritual surrender simultaneously foster a powerful sense of divine presence and drive political engagement? Through immersive fieldwork at revivals, missionary training schools, and church services, Brahinsky investigates the deep pull of tongues prayer. He conducts extensive interviews, participates in worship, and even scans practitioners' brains in MRI machines, capturing the interplay of mind, body, and faith in real time. Tongues of Fire examines a high-energy practice that blends spiritual release with empowerment. Speaking in tongues generates a suggestive certainty, fueling not only personal transformation but also large-scale social activism. Charismatic leaders like Pat Robertson, Jerry Falwell, and Paula White-Cain have harnessed this fervor to reshape U.S. politics, merging faith with ideological movements. This interdisciplinary study-spanning anthropology, neuroscience, and religious studies--offers the most extensive exploration of tongues prayer to date. Tongues of Fire reveals how this practice cultivates both submission and power, creating a force that inspires hope while also driving some of the most polarizing political movements of our time. From revivalist gatherings to the depths of the MRI machine, this book uncovers the hidden mechanics of faith, transformation, and influence-illuminating the far-reaching impact of an ancient practice in today's world.