A few weeks ago, while we were all looking the other way, the triennial survey comparing the world’s educational systems came out. For America, the news wasn’t good. Math scores dropped, while reading numbers weren’t much different from last time. Neither finding puts us on course to lap Singapore anytime soon.

Predictably, of the limited media coverage the survey received in the United States, most articles focused on math and science. Who cares if Johnny can’t read well, so long as he can multiply?

Too often, according to Mark Seidenberg’s important, alarming new book, “Language at the Speed of Sight,” Johnny can’t read because schools of education didn’t give Johnny’s teachers the proper tools to show him how. Economic inequality is a big problem, too, of course, but kindergartners may be grandparents before that can be redressed. Mr. Seidenberg, a veteran cognitive neuroscientist at the University of Wisconsin-Madison, makes a strong case for how brain science can help the teaching profession in the meantime.

His by-now-obligatory waltzing subtitle is “How We Read, Why So Many Can’t, and What Can Be Done About It.” By weight, this isn’t quite right. That first third, “How We Read,” takes up fully two-thirds of the book, leaving only the last hundred pages or so for Mr. Seidenberg’s shrewd diagnoses and prescriptions. Reading “Language at the Speed of Sight” could almost function as a reading experiment itself. Give a volunteer a smart, witty, only occasionally poky primer on the science of reading. Then, on Page 200, replace it with focused, impassioned argument. This test subject, at least, saw his speed and reading comprehension tick up considerably.