Tao-an was a prominent monk and famous Buddhist scholar of Eastern Tsin Dynasty，China. He was ordained as a samanera at the age of twelve. Because of his ugly appearance，he received no special attention and was ordered to do farming chores. However，his cleverness, intelligence，wide knowledge and good memory won his teacher's appreciation several years later. His master changed mind and ordered him to receive full ordination precepts and permitted him to leave the temple to visit and learn with other masters. When he was just over 20 years old，he had gained the complete knowledge of Master Fo Tu-chen at the capital Yeh of the Later Chao State. Henceforth, he always represented Fo-Tu-chen to expose on `sutras` and answer questions. Thus, he won the reputation of "Black dharma practitioner startling the surrounding neighbors."
Tao-an had a deep understanding of Buddhist `sutras`. His annotations on the Prajna `sutra` , the `sutra` of the Practice of the Way，the `sutra` of the Estoric Trace，the Anapanasati `sutra`，etc. were ingreat details and profound. Later，he expounded Buddha dharma in Hsiang-yang，Chang-an and other places to promote the doctrine of "root being nothing" which evolved to become the School of Root Being Nothing，one of the Six Branches and Seven Schools of Prajna Doctrine. He lived in the time of Buddhism being integrated with Chinese traditional metaphysics. Therefore，he always used the terminology of Lao-tze and Chuang-tze to interpret the essentials of Buddhist `sutras`. For example，he once mentioned，"Reduce and reduce again until the ultimate of non-action." (Preface to the Annotation on the Anapanasati `sutra`) and "Keep abreast with the degree of advancement. Tourevery where with a freed mind." (Preface to the `sutra` of the Practice of the Way.) He once said，"Using the Chinese thoughts to interpret Buddhism always defies the true meaning of Buddhism." and "One should be careful in interpreting the Buddha dharma." However, he still referred to non-Buddhist books to interpret Buddha dharma. He still could not avoid the trap of applying the Chinese traditional thoughts to interpret Buddha dharma. From this we may understand that his thoughts were greatly influenced by the Chinese metaphysics.
Tao-an considered that ch'an (dhyna) is the right essence of stopping ignorance，ting (samadhi) is the initial door of subduing mental defilements, zih (stillness) is the marvellous cause of ch'an ting，and，kuang (insig
