The Face in the Frost (review): Methods & Madness (opens in new tab)

The Face in the Frost, by John Bellairs, is a somewhat odd book to include in the Appendix N. Apparently, Gygax was a big fan of it (though he said he read it after D&D was created), as mentioned on Dragon magazine #22; it is also mentioned in the DMG itself (thanks to @John_Cyrano, on X).Dragon #22