Primordial Traditions, the traditionalist and esoteric naturalist organization, has put out a compilation of writings.
Primordial Traditions Compendium 2009 is a collection of original works on Hinduism, Buddhism, Tantra, Asatru, Islam, Mithras, Mayan astrology, perennial philosophy, Paganism, alchemy, esoterica, and mythology from the Celtic, Nordic, Teutonic and Greek Traditions. Inspired by thinkers such as Friedrich Nietzsche, Julius Evola, Immanuel Kant, René Guénon, Huston Smith, Aldous Huxley, Mircea Eliade, and Frithjof Schuon, the book examines religions from a 'top down' perspective and stresses the common ideas found in all major religions and spiritual paths. By examining the foundations of religious thought as philosophical values, the Primordial Traditions Compendium seeks to produce a level of wisdom or gnosis for the reader that is greater than that which would be provided by the study of single religious system. Primordial Traditions continues the work of previous authors in the study of perennial philosophy and examines the underlying metaphysical truths that can be found in all spiritual traditions. The Primordial Traditions Compendium explains religion and spirituality 'as it is' without placing emphasis on any particular religion or spiritual tradition. This examination of spiritual thoughts and practices is of equal value to all readers, from novices to experts in their field. With articles ranging from introductory through to academic levels, the book reveals new information for every reader.
I like how they assign special status to Kant, who popularized transcendental idealism and set up the revolution that was Schopenhauer and Nietzsche. You can find the book here: