C. S. Lewis’s book Surprised by Joy (1955) refers to his mystical experiences. They are seen as transcendental experiences, possessing (in William James’s terms) luminosity and authority and giving access to an inner truth. During his childhood Lewis had felt an intense longing for something elusive, triggered by (say) the fragrance of a currant bush or a piece of poetry. As he said “It is difficult to find words strong enough for the sensation which came over me… It was a sensation, of course, of desire; but desire for what?… And before I knew what I desired, the desire itself was gone, the whole glimpse withdrawn, the world turned commonplace again…” Lewis’s biographer Alister McGrath sees these moments as epiphanies, sparked by Lewis’s intense commitment to literature in which he found great moments of illumination and truth (in Wordsworth, or the sagas), in which everyday human experience is engaged with and in which underlying significances are found.

(Source: Alister McGrath, The Intellectual World of C. S. Lewis, 2014, pp.109-111).