This article articulates some of the major questions and challenges that we, and our many collaborators, have faced while building the DLESE collections. The first part of the article describes questions for which DLESE has found at least tentative answers; the latter part describes tensions and challenges with which DLESE is still grappling. The intended audience includes builders of other education-oriented digital libraries who wish to know what lies ahead, and users of DLESE who wish to understand how DLESE works and why.