J.R.R. Tolkien was a friend and sometime mentor to Lewis. In That Hideous Strength, Lewis alludes several times to Tolkien's Atlantean civilization Numinor (spelt Númenor by Tolkien), saying in the foreword Those who would like to learn further about Numinor and the True West must (alas!) await the publication of much that still exists only in the MSS. of my friend, Professor J. R. R. Tolkien. Villains in both Tolkien's Lord of the Rings cycle and here are very hostile toward the natural world (specifically in the wanton destruction of trees in Tolkien's and the manipulation of life in Lewis's).