The most essential definition as regards the mystic experience in the Western tradition is the experimental knowledge of God. Takeo Iida in D.H. Lawrence as Anti-Rationalist explores the symbolic and mystic connotations of Lawrences oeuvre in its full range. The archetype of what may be called mystic darkness is scrutinised from his early poems up to his major novels, short stories and paintings. The image of the sun shining at midnight, which appears in several variants throughout his work, is carefully examined in the convergent meanings of dark sun or nameless sun, as they occur in The Ladybird, Mornings in Mexico, and in The Plumed Serpent. For Takeo Iida, Lawrences output can be regarded as a lifelong meditation on Light, conceived as godly life-flame, and the author traces this image back to its origin in Pre-Socratic thought and later in the Rosacrucian society or in the Alchemic notion of sol niger, that Lawrence could possibly have known through H. P. Blavaskys work and C. G. Jungs Psychology of the Unconscious (1917), which he read in 1918. The theme is also featured in the Christian tradition with which Lawrence was familiar through the Metaphysical poets since his Lehrjahre at Nottingham High School and at University College.