Advanced search

Frequently Asked Questions

How is the website structured?

The navigation bar appears under the page header and should be largely self-explanatory. If you move the mouse over a term in the bar, a scroll bar rolls out in each case, which contains the further subdivision of the area.

When you move within the Enzyklothek, one or more bread crumb bars appear below the navigation bar.

The bread crumb bars are intended to help you find your way around and to enable you to navigate quickly by pointing to your respective position and the path to that position. If you now click on an area of the bar, for example on "Women's Encyclopaedias", you will be taken directly there without having to move through the navigation tree again.

How do I search in the Enzyklothek?

The Enzyklothek offers you two different search options, the targeted search via the search function and the evaluation of the thematic literature lists via the category function.

Searching via the search functionality

The search slot located under the navigation bar allows you to conduct simple quick searches. You can search for the works of an author as well as for a specific title or a keyword. If you are looking for a specific work, enter the author's last name and a few words from the title in the search slot. This should usually lead to success, provided the work is available in the database.

The advanced search enables you to conduct more targeted searches. You can limit your search to one search field or combine several search fields.

If you enter several words in the general search slot or in a search field of the advanced search, only results containing all the words entered will be returned. You should therefore limit your input to a few identifying words. Full title entries can lead to a loss of information due to different spellings.

With regard to the names of ancient, medieval and early modern authors, it should be noted that there can be very different spellings for these. To make the search easier, name variants have been provided so that you should be able to find your author quickly even if the spelling differs.

When searching for a specific title, you should bear in mind that a title has been subject to numerous changes in the course of its publication history. In other words, in general you should only find some editions of a work in this way, but by no means all of those listed in the Enzyklothek. A list of all editions of a work – irrespective of the actual title of the respective edition – can be obtained by opening the detailed view of a title found and clicking on the specified uniform title in the right-hand box.

If you are looking for publications that appeared in a specific place, enter the official name of the place today. For example, instead of the German Kopenhagen or the English Copenhagen, enter København. However, for literature published in the former German Eastern territories before 1945, the German place names have been retained.

For many publications, no clear year of publication could be determined. In the case of medieval manuscripts, it goes without saying that only in very few cases is an exact year known. In order to be able to assign this literature to a certain time, a probable year of publication was entered for prints, but at the same time reference was made to the uncertainties in the title supplements. In the case of manuscripts, for example, 1101 was entered as the year of publication for one of the 12th century, but the 12th century was entered in the title supplements.

Using the category function

The category function provides you with the data structured as in a bibliography. Unlike in a printed bibliography, however, you can rearrange or select them flexibly according to your wishes.

For example, if you click on the category "Encyclopaedias of classical Antiquity ", the editions of general reference works of antiquity available in the Enzyklothek will be displayed. In the box "Filter results" you can set, for example, how many works from this list are to be displayed per page. You can scroll forwards or backwards within the list view using the arrows on the left and right edges. You can also use the lists at the bottom.

If, for example, you only want to display the works of a particular author, click on Author and select an author. If you choose Claudius Aelianus, for example, a list of 97 editions will appear. If you now want to display only the German-language editions, click on Language and select German.

If you now click, for example, on the title line or on the cover of the German edition of the Thiergeschichten published in 1839-1842, the detailed view will open. Use the arrows on the left and right edges to scroll to the previous or next title in the list of German-language works by Claudius Aelianus. If you click on the cover, it will be enlarged. Next to the cover you will find the complete bibliographical information, below the cover a list of the volumes with links to the corresponding online editions. As far as possible, there is a link to the table of contents or the index. In many cases, however, linking to the table of contents does not produce the desired result, as most providers do not use permanent addresses for links to a specific page. In these cases, please use the preview function of the respective reader to get to the table of contents as quickly as possible.

In the right-hand box in the detailed view you will find the entry ‘Uniform Title’. Click on this to get a list of all editions of this work. The GND entry under Normdaten leads you to the author entry in the German National Library. The VIAF entry opens the page of the "Virtual International Authority File". From here you can go directly to the corresponding entries of numerous national libraries by clicking on one of the national flags.

For further information on the life and work of the author as well as on the present work, click on ‘open’ in the box under References. Links to Wikipedia generally refer to the German Wikipedia. Versions in other languages were only taken into account if there was no German entry. However, the Wikipedia linked here will take you directly to the entries in other Wikipedia versions.

Can I transfer bibliographic data from the Enzyklothek into my literature processing?

The data in the Enzyklothek has been prepared in such a way that the pickers in citavi and zotero react to the entries in the Enzyklothek. This allows you to copy the most important bibliographic data. Additional information of the Enzyklothek such as volume division, table of contents or bibliographical references may have to be copied by hand into a field of your literature management system that seems suitable to you. In addition, the editors of an author's writings and the names of collaborators are not transferred. It is therefore advisable to check the information after an import using a picker and to supplement or correct it if necessary.

Why does the Enzyklothek often contain several links to an online edition of a work?

The retro-digitisation projects of the various providers are not coordinated with each other, so that the same work has sometimes been digitised in several places. Even the provider Google often offers several digitised copies of the same work, because Google digitises entire library collections and does not make a specific selection. What seems superfluous at first glance makes perfect sense. The state of preservation of the digitised works is quite varied. Illegible or missing pages reduce the utility value of a digitised work accordingly. In the case of mass digitisation, there is usually no quality control as to whether all the pages of a work have been digitised in sufficient quality. There are also significant differences in the quality of digitisation by other providers. In addition, servers are sometimes unavailable, digital copies have been given new addresses or even taken offline. Linking to as many offers of the same work as possible is therefore the best way to ensure that you can actually access a digital copy or, in the case of faulty reproductions, that you can possibly consult another, flawless digital copy.

Digitised works from different providers may well be the same digitised work. This is especially true of Google digitisations, which are often offered by the owning library directly or via the HathiTrust Digital Library. In many cases, the Google digitisations have also been uploaded to the Internet Archive. In these cases, too, multiple linking offers advantages. Servers can fail, with one provider the digitised material can be reached directly from Europe, with the other not. And finally, errors occur when the material is uploaded to the net, which is the case with one provider but not with the others.

What are the advantages and disadvantages of the offerings of major content providers?

The differences in quality between the digitised material are enormous. They range from lousy and completely unusable to excellent. In general, the German projects - mostly funded by the DFG - offer good quality. The Bibliothèque Numérique Gallica only shows a high standard of quality in the digitised material of recent years. Older digital copies are sometimes difficult or even impossible to decipher. This also applies to some of the commercial projects available as a DFG national licence, such as "Early English books online" or "The making of the modern world".

With alternative offers, it is therefore worthwhile to do a short quality check before downloading. Here you should not only pay attention to the scan quality of individual pages, but also check whether the pages have been completely digitised. Many readers offer a preview function with so-called thumbnails. Although these are not sufficient to read the pages, they do provide a quick overview of whether pages are missing completely or have only been partially scanned.

Which provider one chooses for online use of a work depends centrally on the functionality of the respective reader. Can I browse the book online or do I have to download the entire work? Is the work searchable? Can I get to the desired pages quickly? Can I link to individual pages? Is the work accessible through a navigable table of contents? The latter is the case, for example, with the digitisation projects of the Düsseldorf University Library, the Berlin State Library, the Göttingen University Library or Nevertheless, in my opinion, the classic Google Reader, not the newer alternative version, is the first choice. While the pages of other providers sometimes build up agonisingly slowly and their servers are sometimes not accessible at all, access to the Google Book Search Reader is reliable and fast. You can scroll through the book quickly and select individual pages. The preview function also builds up immediately. The text recognition is flawed, but at the same time it is the only useful one for works with Fraktur script. The full-text search not only allows you to search the book, but also to search the entire Google Books collection. You can also search for passages in books that are not accessible in full text. The Internet Archive and the HathiTrust Digital Library also have corresponding full-text searches.

Detailed information on how to use Google Book Search and the HathiTrust Digital Library can be found here. Corresponding explanations on the Internet Archive can be found on this page. In addition, the corresponding instructions of the respective providers should be consulted.

If you download the PDF file of a work from Google, the HathiTrust Digital Library or the Internet Archive, you will also receive the corresponding OCR text with the facsimile, which you can search or export. However, downloading works from the HathiTrust Digital Library is only available to readers of one of the libraries in the network. This is where the Hathi Download Helper comes in. The Hathi Download Helper and the Internet Archive also allow direct saving of the OCR text.

Why does a link not lead to a full view of a work?

The reasons why a link does not lead to a full-text view can be very diverse and therefore require a differentiated answer.

Retro-digitised works in Google Book Search and in the HathiTrust Digital Library that are younger than 140 years are often not displayed in full view in Europe. In the US, this usually only applies to works younger than 90-100 years. If a work that meets these criteria also has a digitised copy in the Internet Archive, it is generally recommended that you use this link, because works posted in the Internet Archive can be viewed worldwide without restrictions. However, you should note that the Internet Archive does not use Google's text recognition. Unfortunately, the text recognition used by the Internet Archive is unusable for books set in Fraktur. The easiest way to find out whether a Google Digitisation has been uploaded to the Internet Archive is to copy the relevant identifier into the Internet Archive search slot, i.e. the characters between the equals and ampersands of a Google link. In the following example

the character string ucZFAAAAcAAJ. If a work has not yet been uploaded, you can also help to ensure that the work is accessible regardless of where it is dialled in by uploading it to the Internet Archive.

In other cases, the use of a proxy is required to read or download the work. In individual cases, this route may also lead to a result if the work is more than 140 years old, but is nevertheless not accessible in Europe due to inadequate metadata. Detailed information on how to proceed when using a proxy can be found in Wikisource.

Sometimes, however, it also happens that a digital copy is no longer available. Unfortunately, it is not clear why these works can no longer be viewed in Google Book Search. Obviously, hints to Google rarely lead any further.

You cannot directly access works that are not in the public domain in the Internet Archive. However, you can borrow them virtually. To do this, however, you must register. Registration and borrowing are free of charge.

Works not in the public domain are only partially visible in the Google Book Preview. Nevertheless, they have been linked, as important information can already be gleaned from the excerpts. They make it easier to decide whether the book is helpful for one's own research. The scope of the accessible pages varies from publisher to publisher, and sometimes also from day to day. It also happens from time to time that a book has been removed from the Google Book Preview in the meantime, so that the link actually leads nowhere. When linking to specific pages, it is also possible that the pages that can be viewed have been changed. It is therefore advisable to check whether you can access one of the following pages to get an impression of the contribution.

Unfortunately, works and contributions for which the DFG has acquired a national licence cannot be viewed directly. Access to the respective databases requires a personal login. The link used in the Enzyklothek will therefore regularly take you to the corresponding registration page. If you do not have the necessary login data, you can obtain them by registering if you are a permanent resident of the Federal Republic of Germany. Alternatively, you can of course also use the access via your library account.

Occasionally, links have also been provided to digital copies for which there are national licences in Denmark, the Netherlands or Norway. They can only be viewed with an IP assigned to these countries, but not from other countries, unless a proxy is used.

A library account is required - at least for the most part - to use the following services:

Biographisch-Bibliographisches Kirchenlexikon
Project Muse

To find out whether your library or another library in your area allows access to these services, please visit

However, linking a digitised work in the Enzyklothek may not lead to a full-text view because the link is no longer up-to-date. Even so-called permanent links (persistent identifiers) such as URN or DOI sometimes lead nowhere. Since the digital copy is generally still accessible on the net, you should start an appropriate search yourself.

How do I find digital copies on the net?

If there is no online edition listed in the Enzyklothek, or if no link is working any more, you will unfortunately have to do the search yourself.

Sometimes just entering a search term in a general search engine or in a meta search engine will lead to a result. It is also recommended to start a more intensive search via the metacatalogue KVK (Karlsruhe Virtual Catalog) of the Karlsruhe Institute of Technology. The KVK allows you to search several library catalogues in parallel and at the same time limit the search to digital media. Other recommended metacatalogues are:

If you have not found anything in these metacatalogues for the relevant providers Gallica, Google, HathiTrust Digital Library as well as the various national digitisation projects, this does not yet mean that these providers do not have the desired digitised material. Bear in mind that sometimes different names are used for the same person and that the titles may have been entered differently in the catalogues to be searched. In addition, as already mentioned, Google and the HathiTrust Digital Library will rarely give you a useful result without using a proxy for works that are younger than 140 years. In this case, you have no choice but to search the catalogues of the above-mentioned providers again individually. If this does not lead to a result either, you should consider in which region the book could most likely have been digitised and research in the catalogues there. The following internet addresses provide an overview of digital libraries:

Can I unlock public domain works at Google Books and in the HathiTrust Digital Library?

It often happens with Google Books and the HathiTrust Digital Library that digitised works in the public domain are not displayed in full text. Detailed information on how to obtain access to these works can be found here. In the case of Google digitised works, it may also be helpful to contact the library from which the book was digitised rather than Google directly.

Can I be informed about new works being added to the Enzyklothek?

You can subscribe to news on via RSS feed. Simply click on the RSS symbol in the sidebar or use this link: RSS

How can I help to improve the Enzyklothek?

The Enzyklothek is a participatory library and can only get better thanks to your cooperation. Report broken or missing links, editions or works that are not included.

How was the bibliographic data of the Enzyklothek obtained?

The bibliographic data of the Enzyklothek were obtained through extensive analyses of library catalogues, bibliographies, databases as well as the relevant specialist literature and through internet research. As far as possible, this data was checked and supplemented using the corresponding originals or digital copies.