Digital course libraries are educational Web applications that contain instructional materials to assist students’ learning in a specific discipline (course). To address the critical issues of findability and reusability of learning resources, we propose a general framework for standards-based, ontology-aware course libraries and use it to develop an environment for building, maintaining, and using such libraries. The proposed environment, TM4L (Topic Maps for Learning), is based on the new ISO standard XML Topic Maps that provides a paradigm for organizing and retrieving online information and for interchanging semantic information on the Web. In this paper we present the TM4L authoring tool for creating ontology-aware Topic Maps-based repositories of learning materials (TM4L Editor).