Heart-Wood from the Bo Tree by Buddhadasa Bhikkhu.

Three talks given to a Dhamma study group in Siriraj Hospital, Bangkok, on 17 Dec 1961 (“The Essential Points of the Buddhist Teachings”), 7 January 1962 (“Emptiness”), and 21 January 1962 (“The Way to Practice in order to Abide with Emptiness”).

Translated from the Thai (แก่นพุทธศาสน์) by Dhammavicayo. [Thammasapa, Bangkok], n.d. 104 p.