In the text are elaborated new terms, linked to the development of the digital, virtual, electronic, hybrid, so called Library without walls. The author gives a brief summary of theoretical statements from the newest world literature about Digital Libraries, as She tries to make a comparative analyze of different definitions and elementary thesis of Digital Libraries. A special attention is consecrate to International Projects of creation of Digital Libraries: The European Library (TEL), Bibliotheca Universalis, Memory of the World (UNESCO). The Summary of the situation, regarding the Development of the Digital Library in the World, prepared by IFLA and UNESCO, is given at the end of the Paper.