Alan Hull Walton, writing in Books and Bookmen, declared:
... in an age of talented mediocrity, [Colin Wilson] is blessed with far more than talent – he is blessed with insight, sincerity, humility, an extraordinarily wide learning (comparable to that of the ‘universal man’ of the Renaissance), and also manifests something of the breadth of genius of a Goethe. ... His new book ... is by far and away his best work to date, and worthy to be placed on the same shelf alongside William James, F. W. H. Myers’ monumental study of Human Personality ... and Frazer’s Golden Bough. ... A review of a thousand words ... cannot do justice to a book of this calibre. ... The Occult is a valuable ‘must’ for anyone with the remotest interest in the future of civilised man.
