  Manual subject indexing in libraries is a time-consuming and costly process
and the quality of the assigned subjects is affected by the cataloguer's
knowledge on the specific topics contained in the book. Trying to solve these
issues, we exploited the opportunities arising from artificial intelligence to
develop Kratt: a prototype of an automatic subject indexing tool. Kratt is able
to subject index a book independent of its extent and genre with a set of
keywords present in the Estonian Subject Thesaurus. It takes Kratt
approximately 1 minute to subject index a book, outperforming humans 10-15
times. Although the resulting keywords were not considered satisfactory by the
cataloguers, the ratings of a small sample of regular library users showed more
promise. We also argue that the results can be enhanced by including a bigger
corpus for training the model and applying more careful preprocessing
techniques.
