Alan Watts
Author: Jelte
Introduction to Zen Buddhism
Suzuki
In my opinion the best short work available on the subject in the English language.
Buddhism
Christmas Humphreys
A good introduction to, and overview of, the main branches of Buddhism. Intended for those willing to garner a historical understanding, but not designed with a view to aiding the practice of Buddhism. Whatever that is.
The Book
Alan Watts
A whimsical introduction to transcending the Ego.
Die Welt als Wille und Vorstellung

Arthur Schopenhauer
[The World as Will and Representation]
Schopenhauer’s major work. An astonishingly lucid, and satisfyingly self-consistent, integration of Western and Eastern thought.
On the Principle of Sufficient Reason

Arthur Schopenhauer
An excellent and under-appreciated treatise on the possible sources of knowledge.
UpaniÅŸads
The Road to Reality

Roger Penrose
An ambitious attempt at bringing the reader to the forefront of current understanding of the physical world. Committing.
Primates and Philosophers
Frans de WaalBy arguing that humans have many moral elements in common with primates, de Waal attacks what he calls ‘vernier theory’ – the theory that ‘morality’ is a superficial shell surrounding an essentially selfish human core.
Prolegomena to any Future Metaphysics

Immanuel Kant
A tough but immeasurably satisfying read. Very worthwhile for anyone considering delving into the Critique of Pure Reason.