Last month’s issue of Boston Review has a very good essay by James Heckman, and follow-up discussion. Heckman’s essay argues forcefully for early childhood interventions of various kinds as efficient means for mitigating inequality of opportunity.
I’d especially recommend that you read Charles Murray’s comment, just so you can read Heckman’s (devastating) response, but also Annette Lareau’s and David Deming’s. And, if you want, mine and Swift’s.

One thing I am curious about. Heckman is consistently accused by lefties of not understanding that poverty, not parenting, is the fundamental problem. For all I know that is true, and it is not impossible that I have a tin ear, but when I read his essay (and hear him talk etc) everything he says is consistent with the (entirely reasonable) assumption that as things stand, though the fundamental problem may well be poverty, elected officials are pretty determined to do very little to reduce poverty in general and child poverty in particular, so we need to look for policy levers that would improve the prospects of poor children without addressing their poverty. (And, if by some chance, this pessimistic assessment is wrong, still the measures he proposes would play an important role during the long transition to a more equal society). Is it just because he is known to be, broadly speaking, a conservative that people read him the less charitable way? Or am I, indeed, missing something?