Steven Brill’s Class Warfare is an immensely readable take on a slice of the “school reform” movement and an intriguing look at some key individuals in that effort. But, as is shown by its treatment of philanthropy, the book is perhaps more revealing for what its author omits—and how its blinkered view can mislead readers on big questions.

Grand claims about the transformative power of technology in education are common, yet decades of high school redesign have yielded mixed results. One of the most widely touted efforts to tackle these challenges has been the School of the Future in the Philadelphia School District, created in 2006 through a...