Heart-Wood from the Bo Tree (Making Mutual Understanding Between Religions: Series 3) by Buddhadāsa Bhikkhu.

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

Translated from the Thai (แก่นพุทธศาสน์) by Dhammavicayo. Distributed by the Buddhadāsa Foundation, Nonthaburi. Suan Usom Foundation, Bangkok, 2530 [1987]. 99 p.