It is hard to come up with a coherent reaction to this book. The emphasis on detail rather than narrative and theory means that from a blogging perspective there is not a lot to "react" to, just absorb. But on page 81 the authors point out that while a large fraction of the variance in test scores is heritable (note that "heritable" just means that you get it from your parents, whether via genes or upbringing), a system that based privileges solely on test scores would only let about a third of upper-middle-class kids stay in the class into which they were born. I am not going to judge the level of empirical support for their claim in 1972; I will just note that while test prep is hardly perfect it can be effective, and the most effective test prep is not a few weekends of Kaplan but rather 12 years of good schooling. To the extent that upper-middle-class educational arms races have heated up in the past four decades (and I freely admit that my anecdotal observations on that point are no substitute for real data) this could undermine some of that prediction by Jencks et al. If you tell the upper classes that their kids can no longer get into desirable universities based solely on last name (and legacy admits are fewer in percentage, even if by no means gone) then they will not simply shrug. They will try to compete and play to their advantages. This is the same response that I had to Guinier's book.