This contribution—originally prepared as a PhD thesis—deals with the Köŋül Tözin Ukıtdaçı Nom (“The Book of Teaching of the Essence of Mind”), an Old Uighur text from the Mahayana branch of Buddhism which deals with the Mind-only theory. This text belongs to the later period of Uighur from the Mongolian era. It is written by Vapshi Bakhshi and copied by Chisön Tutung. It is registered as Or. 8212 (108) in the library of the British Museum. The text shows the whole extend to which Buddhist thought had influenced religious and philosophic thinking of the Uighur. At the same time it provides us with lots of linguistic material which reveals the state of development and refinement of this section of the Uighur lexicon. The text is also of some importance in the framework of Buddhistic studies, since Chinese or Sanskrit versions have not been found yet. Thus, the investigation and discussion of the Uighur terms which are used to express the Buddhistic concepts discussed in the text are of special interest not only for Turkology but also for Buddhistic studies.

The work consists of seven chapters. The introduction gives general informations about the text and its content. There follow the transcription of the Uighur text (consisting of 30 folios and 405 lines) and its translation into Turkish. In the fourth part the philosophic and religious content of the text is analyzed and explained. In the following part of the work, Buddhist terms, phraseology etc. are presented and compared with the corresponding lexical inventory in other Uigur texts. The sixth chapter encompasses three glossaries, an analytical glossary of the text, a Sanskrit–Uighur glossary, and a glossary of paired expressions. Finally, the last chapter presents the results of the grammatical, and semantic investigations together with the Buddhological considerations.