The paper presents some aspects of an ongoing project aimed at the development of a methodology and proper software tools for building academic digital libraries. An ontology-based approach is suggested in order to standardize the semantic annotation of the library resources and to facilitate the implementation of the functionality of the search engine. The emphasis of the discussion falls on the analysis of the requirements of the main types of users of academic digital libraries and the corresponding authoring tools implemented in a particular academic digital library being under development at the Faculty of Mathematics and Informatics, Sofia University. These tools are oriented to the teaching and research staff members and the library administrators who may create and edit catalogue descriptions and upload library resources in the proper repositories. Some solutions of the variety of problems concerning the development of adequate mechanisms for semantics oriented search in multilingual academic digital libraries are discussed in brief.