When Eric Kalenze was getting his master’s degree in education in the 1990s, he was immersed in pedagogical theories that have prevailed at ed schools for a century. Learning proceeds best, he was told, when focused on skills like critical thinking and tailored to the interests of individuals. Rather than assuming the role of a “sage on the stage,” depositing facts into children’s passive brains, a teacher should be a “guide on the side,” enabling students to learn primarily through inquiry and hands-on activities. Kalenze was dubious. None of this jibed with what he recalled of his own school experience or his gut-level sense of what works.