The Digital Library of the Catholic Reformation makes the documentary riches of this era accessible, adding functionalities that maximize the flexibility with which researchers can search, view, organize, and manipulate this historically important source material. With new content uploads occurring on a regular basis, the database offers a constantly growing treasury of documents, including papal and synodal decrees, catechisms and inquisitorial manuals, biblical commentaries, theological treatises and systems, liturgical writings, saints' lives, and devotional works.

The Digital Library of Classic Protestant Texts gives researchers access to an extensive range of seminal works from the Reformation and post-Reformation eras. With new content uploads occurring on a regular basis, the database offers a constantly growing treasury of theological writings, biblical commentaries, confessional documents, and polemical treatises written by more than 300 Protestant authors.

Walter De Gruyter publishes a wide variety of content covering humanities, medicine, the sciences and law. The "De Gruyter Online" platform provides access to title information and the electronic content for De Gruyter journals and books under one roof. Users from the MPG have access to following products: * De Gruyter Journals and Yearbooks - current content of selected serial titles available on the platform (last 13 volumes) * De Gruyter Journal Archive - backfile content of 150 titles * De Gruyter Online / Research Now E-Journal Archive - about 50 journals focusing on research in economics, formerly published by Berkeley Electronic Press until 2022 * De Gruyter eBooks - a collection of purchased e-books which is continuously extended by single e-book acquisitions by MPG libraries

The Mohr Siebeck eBooks collection contains academic books, series and multi-volume works in the subject areas of theology, history, phiosophy, law, economics and sociology. The book selection is continuously extended by single e-book acquisitions and series purchases by MPG libraries.

Facsimile edition of the "Patrologia Graeca", edited by Jacques-Paul Migne from 1857 to 1866 in more than 160 volumes. The database comprises works of the Greek church literature beginning with Pseudo-Clemens (100 AD) up to Kallistos (1478) and thus makes available the important Greek Christian authors and the most influential works of theology, philosophy, history and literature of the late ancient world and the early Middle Ages. Texts are made easily accessible by an index of contents in Latin and Greek language, by an index of authors, a title index and an index of subject. All of these indexes are full text ones.

The Patrologia Latina Database is an electronic version of the first edition of Jacques-Paul Migne's Patrologia Latina, published between 1844 and 1855, and the four volumes of indexes published between 1862 and 1865. Patrologia Latina comprises the works of the Church Fathers from Tertullian in 200 AD to the death of Pope Innocent III in 1216. The complete Patrologia Latina is included with all prefatory material, original texts, critical apparatus and indexes. Migne's column numbers, essential references for scholars, are included.

The SpringerLink platform provides MPG staff with access to a huge collection of English and German eBooks from 2005 onwards, as well as the English and the German collection of the Springer Book Archive (1842-2004). In addition, the content of selected book series is available. Includes major reference works and dictionaries. Max Planck researchers who publish a monograph or edited volume with Springer Nature as an Open Access eBook receive a discount on the standard Book Publishing Charge. MPDL covers the costs remaining on a pro rata basis. Further details are available on the MPDL website.