Here’s a review that offers a good introduction to the book, Elmer Crowley: A Katabasic Nekyia, with sample illustrations: http://htmlgiant.com/reviews/elmer-crowley-a-katabasic-nekyia-by-tom-bradley/#more-119147 

Raves from Gwendolyn von Taunton, Richard Kaczynski, Fortean Times: http://tombradley.org/elmer_more_raves.html