There are many thousands of perennial wisdom books and nonduality teachers past and present sharing the teachings of Oneness, Nonduality, Advaita Vendanta, Taoism, and more.
The writings of the sages Nisargadatta, Lao Tzu, Ramana Maharshi, Rumi, the Buddha, Krishnamurti and many other reflect the wordless and incomprehensible and paradoxical message these sages appeared to point towards. These nonduality teachers grokked the paradox of what is seeming to appear and warned against swallowing and endorsing any concepts and words.
Words, oral or written, cannot ever describe what is…what is cannot be comprehended with the human brain. So how do we learn the Truth? It seems some measure of Mystery and Grace seems to peel the untruth from the weary human eye and brain after long investigations into self inquiry reveal what has never not been here, now…as this perfect moment.
Below are the nonduality and perennial wisdom books that were my constant companions on the spiritual path. I still enjoy the aliveness of these readings now.
The Perennial Way – translations by Bart Marshall – Ashtavakra Gita and Heart Sutra in particular
Ask the Awakened – Wei Wu Wei – all books by Wei Wu Wei (Terence James Stannus Grey)
Psychology of the Observer – Richard Rose
The Direct Mind Experience – Richard Rose
The Albigen Papers – Richard Rose
I Am That – Sri Nisargadatta Maharaj
Consciousness and The Absolute – Sri Nisargadatta Maharaj
The Mystique of Enlightenment – U.G. Krishnamurti
Perfect Brilliant Stillness – David Carse
On Having No Head – Douglas Harding
A Course in Miracles – Foundation for Inner Peace
Sunyata – Life and Saying of a Rare-born Mystic – edited by Betty Camhi and Elliott Insenberg
Collision With the Infinite – Suzanne Segal
Solving Yourself – Yuben de Wu Hsin – translation by Roy Melvyn
Experience of No-Self – Bernadette Roberts
Path to No-Self – Bernadette Roberts
The Real Christ – Bernadette Roberts
I Am – Jean Klein