He is best known for the research monograph Concept and Reality in Early Buddhist Thought and the exploratory study The Magic of the Mind.
He renounced his post in 1967 to enter the Order of Buddhist monks under the name Kaṭukurunde Ñāṇananda in the forest monastic tradition of Sri Lanka.
Ñāṇananda maintained a simple and austere way of practice with a strong commitment to strict Vinaya standards until his death.
This penetrative study[5] shed new light on the early Buddhist views on the psychology of perception,[6] the conceptualizing process and its transcending.
[7] The discussion focuses upon two important but controversial terms found in the Buddha's discourses: papañca and papañca-saññā-saṅkhā[8] Ven.
Ñāṇananda was the first to analyze the unique grammatical shift found in the sections in which the compound papañca-saññā-saṅkhā appears in the Madhupiṇḍika Sutta (MN 18),[9] which he regards as the “locus classicus as it affords us a clearer insight into the problem of papañca”.
[12][13][14][15][16][17][18][19] The book was introduced as "an imaginative interpretation of the Buddhist critique of conceptual thought in the Pali tradition" in the Encyclopedia of Religion.
[20] A critical assessment of Concept and Reality has been published by Stephen Evans in Buddhist Studies Review (2017),[21] with a rejoinder by Bhikkhunī Dhammadinnā (2017).
[25] The book attempts to draw out the psychological and philosophical implications of the text, centered on a discussion of Paticcasamuppada as a golden mean which freely transcends the dualities of existence and non-existence and mind-and-matter.
While this collection develops on his earlier works, the Nibbana sermons are presented with a more pragmatic outlook to benefit those who are keen on realizing this ultimate goal of Buddhist practice.
[27] Venerable Ñāṇananda's most recent work is The Law of Dependent Arising - The Secret of Bondage and Release (2015) ISBN 978-1517706340, a series of sermons dealing with the Buddhist concept of Paticcasamuppada.