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About Thema

Thema – the subject category scheme for a global book trade

Thema is a relatively new global subject classification system for books, which has already gathered wide international participation and adoption.

Thema is a multilingual subject category scheme designed to meet the needs of publishers, retailers and trade intermediaries in all sectors of the global book publishing business. It is managed by EDItEUR and an international group of stakeholders, and is free to use. Thema aims to enhance the merchandising, discoverability and potential sales of books by simplifying the communication of accurate and detailed subject information across international markets and reducing the need to maintain numerous national subject schemes.’

Thema is intended for use by all parts of the book business, from publishers to retailers, and even in public libraries. Unlike other book trade subject classifications, it aims to be globally applicable. And in contrast to various academic library classifications that are used internationally, it is tailored for commercial use within the trade. It is a flexible standard that allows each market to retain its unique cultural voice while still presenting a unified subject hierarchy that rationalises book classification. The goals of the scheme are to reduce the duplication of effort required by the many distinct national subject schemes, and to eliminate the need for scheme-to-scheme mapping that inevitably degrades the accuracy of classification, by providing a single scheme for broad international use. It can be used alongside existing national schemes like BIC, BISAC, NUR or CLIL, and although this is not a primary goal, it has the potential to eventually replace them.


The Thema project was launched at the Frankfurt Book Fair in 2012, and a pilot draft of Thema version 0.9 was published on 19th April 2013. Early development was guided by a Themaboard and a technical group, and drew upon earlier work with an internationalised version of the BIC subject scheme. From mid-2013, ongoing management and governance of the scheme was handled by EDItEUR using a similar model to that used successfully with ONIX. Thema goes further than earlier subject schemes intended for commercial use to ensure that it is internationally relevant, by combining a robust selection of shared subject categories with an expansive list of post-coordinated subject qualifiers which can include national variants and extensions. It is available in a number of languages. Thema provides a structure that has global application while meeting local needs.

The first ‘live’ version of Thema was launched in late 2013, and version 1.0 was presented (PDF) at the CONTEC Conference during the Frankfurt Book Fair 2013. An initial spreadsheet of the subject catgories and qualifiers (in English), a set of basic user guidelines, a mapping from the BIC 2.1 subject scheme to Thema, and a simple interactive category picker (with partial translations in six languages) were made available on 31st October 2013. Full translations of the scheme plus an extended multilingual version of the interactive picker (including full translations in German, French, Norwegian) and other resources followed. Further translations became available during 2014. The ‘sunrise’ date – the first date on which it was reasonable to include Thema classifications in product metadata (eg in ONIX files) - passed on 31st December 2013, and many implementations are now available in software vendors’ product management systems.

Thema version 1.1 – improved with around 125 extra categories and numerous other small refinements – was launched on 30th November 2014, initially in English only, though translated resources were added soon after, and further improvements to the translations continue to be made. Version 1.1 was 'additions only', meaning that it was fully backwards-compatible with version 1.0: old metadata records did not need to be revised, but the new categories added provided for improved mappings from legacy schemes and greater precision in the classification of children's and scientific titles in particular. This additions-only policy continues in place up to at least version 1.3. The number of available languages with complete or nearly complete translations reached 10 in mid-2015, and a sizeable list of national extensions (primarily geographical, but also covering national educational curricula) was added in October 2015.

Thema version 1.2 was released at the end of May 2016. It was again fully back-compatible with earlier releases and contained around 125 additional subject categories and qualifiers, and around 180 new national extensions. These additions increased the power and expressivity of the scheme. Version 1.2 was available in well over a dozen languages. In 2017, a further large tranche of new Educational and Geographical qualifiers were added to the scheme, to improve the precision of the qualifiers when used for textbooks, travel guides and so on.

Thema version 1.3 – the most throrough revision of the scheme so far – was released at the end of April 2018. This version added about 260 new core subject codes, plus 150 new qualifiers (of which about 85 were national extensions held over from 2017). There were also nearly 500 slight changes of wording in the English headings and notes, intended to make the meaning of each category easier to understand, particularly for those where the scheme is not available in their native language. Thousands of similar adjustments have subsequently been made in other languages.

In 2019, the number of languages publicly available reached 18 (at least three other languages exist in private translations), and in April a small set of further national extensions were added. A number of mappings (from BISAC, WGSneu and CLIL to Thema) were also made freely available via the EDItEUR website.

Thema version 1.4 was released in April 2020. adding nearly 150 new core subject codes and 550 new qualifiers (the vast majority of the latter are national extensions). The latest Thema 1.4 resources are available hereResources specifically for verson 1.3 are still available here, and earlier versons are archived here.

Thema is managed by EDItEUR through a number of national interest groups and an International Steering Committee, in a similar manner to ONIX for Books. The first elected chair of the Thema International Steering Committee was Howard Willows (of Nielsen Book, though in this case representing the UK Thema national group), and he was succeeded by Jesús Peraita (of Neturity and FGEE, representing the Spanish Thema group). The scheme is free of charge for all to use, subject to EDItEUR’s normal, highly-permissive licence. No registration, fee or membership is required to implement and use Thema.

Thema in the press and other resources


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