本文原用英文寫出，且於數年前發表於「中國文化」 Chinese Culture，Vol. XX，Nos.I-2. 1979. 現使之以漢 文出現，藉公諸同好. 同時我們希望它能鼓勵對敦煌佛教文 獻感興趣的同仁繼續向此方向努力云云.
Being buried in the dust for a period of over a thousand years, the Twenty-two-Dialogues on `Mahayana` Buddhism by T'ang-Kuang of the T'ang dynasty was discovered at the Tun-huang caves in the beginning of this century in fragmentary manuscripts. In 1973 the author of the persent paper had the opportunity of examining the various manuscripts related to this work at the `Bibliotheque` Nationale，Paris, and the British Museum，London. Later he spent several years editing，collating and correcting these versions, so that it could be restored to its original form. It is hoped that we now have a version which is very close to the original composition，This article is an introduction. The newly edited version very close to the origined version along with notes will be published in due time.
The main points for discussion will be as follows:
1. To examine the Sino-Indian Buddhist debate held in Lhasa which was a confrontation between the sudden enlightenment doctrines of the Chinese Ch'an school and the traditional teachings of Indian Buddhism. The result was that each side claimed victory based on its sectarian sources.
2. To search for references concerning the principal participants in the dialogues and their relation to the Sino-Indian debate.
3. To study the historical development of Tibetan Buddhism and the cultural as well as diplomatic relations between Tibet and China.
4. To analyse，explain or criticize the philosophical or historical content of the work. The title of this paper may be called："A Commentary on the Twenty-two Dialogues".
5. As the name of T'an-Kuang was nowhere included in the Chinese Buddhist historical records, much time was spent on the following areas：i. His life and times; ii. His relation with the Hsi-ming monastery and its cultural activities; iii. His return to the Ho-hsi region and his literary activities and iv. His influence on Tun-huang Buddhist studies.
This paper was originally wtitten in English and published in "Chinese Culture". Vol.XX, Nos.1-2，1979. As it has a Chinese version now，the Chinese reading public may share the fruit with us. At the same time we sincerely hope it may encourage those who are interested in the study of Tun-huang literature to continue to press forward in this direction.
