Softcover. Malden, NA, Wiley-Blackwell, 1st, 1998, Book: Very Good, Dust Jacket: None, 272 pages. Softcover. A very clean, unmarked copy with only minor edgewear.

Softcover. Great Britain, Cambridge University Press, 1st Paperback Edition, 2015, Book: Very Good, Dust Jacket: None, 487 pages. Softcover. B/w diagrams throughout. Pages clean adn bright. Binding good. Wrapper excellent, glossy. In beautiful condition. "In On the Fourfold Root Schopenhauer takes the principle of sufficient reason, which states that nothing is without a reason why it is, and shows how it covers different forms of explanation or ground that previous philosophers have tended to confuse."