Controversy and strong official disfavor failed to shake Duane Jeffery's tenacious efforts to fit the theory of evolution into the doctrines of the Church of Jesus Christ of Latter-day Saints. Steven L. Peck traces Jeffery's life from his rural upbringing and training as a geneticist through a career marked by conflict around his dedication to bring science into classrooms at Brigham Young University. As Peck shows, Jeffery met resistance from Church leaders with a patient, years-long campaign to build understanding. He corrected misinformation within Church culture and educational systems and defended science's place in education and faith. Jeffery's commitment to honesty, intellectual curiosity, and openness encouraged and smoothed often tense conversations about the union of scientific evidence and religious faith. At the same time, his work gave Brigham Young credibility as a research university while his writing and mentorship inspired later generations to continue the dialogue.An overdue look at a singular figure, Duane Jeffery tells the story of the scientist whose work reshaped how many Church members understand evolution.