MIA contains the writings of 592 authors representing a complete spectrum of political, philosophical, and scientific thought, generally spanning the past 200 years. Being a communist means working for the self-emancipation of the working class; it means striving to unite the working class, in all its diversity, in the struggle to overthrow capitalism. In the 1840s, Marx and Engels placed communism on a scientific footing through the theory of dialectical materialism. Marxists are those who have continued this ever since. If any one of the following criteria apply, the MIA Collective may decide to place the writer into the Reference Archive: (i) they pre-date Marx and Engels, (ii) they specifically reject Marxism, (iii) their work is practically and theoretically unconnected or hostile toward the workers movement, (iv) their work is idealistic or lacking in dialectic. Where a writer contributes to Marxist theory and practice for a part of their life, while other works lie outside of Marxism, then the whole of their writing will be placed in the Marxist Writers' Archive.Contains: Karl Marx/ Friedrich Engels - Werke ; Rosa Luxenburg; August Bebel; Antonio Gramsci ...

The Max Planck e-Book Index provides holdings of electronic books licensed for users in the Max Planck Society.

The Max Planck Journal Index provides holdings of a great range of printed journals available within the Max Planck Society. Besides, it contains metadata of electronic journals as loaded from the EZB. The database is updated regularly from the ZDB (twice a year) and the EZB (monthly).

MPG.PuRe is the publication repository of the Max Planck Society. It contains bibliographic data and numerous fulltexts of the publications of its researchers. The repository is based on PubMan, a publication repository software developed by the Max Planck Digital Library. PuRe was introduced in the MPG in May 2009 and replaced the former institutional repository eDoc.

The Library and Information Service (BIS) is the joint library for the Max-Planck-Institute for Meteorology (MPI-M) and five institutes of the Center for Earth System Science and Sustainability. The cooperation with some university institutes regarding the library exists since the foundation of the MPI-M in 1975.

The Otto Hahn Library is a special scientific library which provides the institutes on the Max Planck Campus at Göttingen-Nikolausberg with literature and information. Its holdings primarily consist of literature covering the fields of research of the institutes Multidisciplinary Sciences and Dynamics & Self-Organization.

Gemeinsamer Katalog des Max-Planck-Instituts für Biogeochemie und des Max-Planck-Instituts für Chemische Ökologie, Jena.

A collaborative effort of the Networked Digital Library of Theses and Dissertations (NDLTD), OCLC, VTLS, and Scirus, the NDLTD Union Catalog contains more than one million records of electronic theses and dissertations. For students and researchers, the Union Catalog makes individual collections of NDLTD member institutions and consortia appear as one seamless digital library of electronic theses and dissertations.

Various dictionaries are available.

Project Gutenberg is a volunteer effort to digitize and archive cultural works. Founded in 1971 by Michael Hart, it is the oldest digital library. Project Gutenberg's mission is "To encourage the creation and distribution of eBooks".

Refubium is a service of the university library of the Freie Universität Berlin. As an institutional repository it collects documents, dissertations, postdoctoral theses, and research data.

The research database "Scholarly Journals and Newspapers in the Age of Enlightenment", conducted by the Göttingen Academy of Sciences, provides an extensive systematic index to German-language periodicals of the 18th century. It is based on the long-term research project "Scholarly Journals and Newspapers", which besides indexing and digitizing these scholarly journals aims to visualize their significant role for the emergence and structures of the "Enlightened scientific community". The project focuses on interdisciplinary journals, comprising of original contributions, book reviews, scholarly news as well as all facets of critique. The interactive online database also includes the data of the two previous research projects "Index of German-language Periodicals" (IdZ 18) and "Systematic Index of German-language Review Journals" (IdRZ 18). By the year 2025, it will give access to 323 periodicals (ca. 2,775 volumes and ca. 1,260,000 pages), spanning the time period 1688-1815.

The BSZ develops and maintains the SWB database in cooperation with 1,200 libraries in Baden-Württemberg, Pfalz, Saarland and Sachsen. The online catalog offers bibliographic data free of charge: Monographs, periodicals, articles, loose-leaf collections, off-prints, conference proceedings, university publications, reviews, abstracts, tables of contents, maps, music, audiovisual material, microforms, electronic resources (data media), online resources; scientific and popular literature from all subjects and in all languages from the 15th century to the present; scientific literature (according to the DFG special subject fields programme) from theology, ancient orient, art, music, archeology, law and criminology;

In addition to the 75.000 prints belonging to the basic content, VD16 comprises a supplement of more than 25.000 new titles. New titles are added continuously through acquisitions by the Bayerische Staatsbibliothek for the Collection of German Prints, as well as through data provided by national and foreign libraries.

The ZDB is the world’s largest specialized database for serial titles (journals, annuals, newspapers etc., incl. e-journals). The ZDB contains more than 1 million bibliographic records of serials from the 16th century onwards, from all countries, in all languages, held in 4000 German (and some foreign) libraries, with holdings information. It does not index individual journal articles.