There are some genetic markers and traits that vary more between races than individuals, but overall genetic variation within a specific population is much greater than the variation between races.
But it doesn't follow that race couldn't possibly be a useful biological classification. Even if the distributions of two groups overlap strongly when any one trait or marker is considered, the groups might still be easily distinguished when you look at the whole configuration space---consider an illustrative diagram.
I want to learn what's well-understood about education. I expect to launch myself into some endeavors in teaching the first few levels of epistemic and instrumental rationality - ie., critical thinking and problem solving. I'm a little suspicious, though, of the scattered educational texts that I've so far read. In particular, education seems like a field where it's easy to have motivated thoughts, and hard to gather good data.
With my background (Math and CS) I'm a little at sea in educational literature. Does anyone know of good, reductionist-grade or evidential-grade, introductory texts in education?