If I have to pick a single rule book as my favorite from the Dungeons & Dragons library, I always go with the Monster Manual. I'm quite partial to the art within, especially those vintage David Sutherland and D.A. Trampier drawings from the original AD&D edition, not to mention the vast menagerie of potential foes for PCs. I have to admit that many of my favorites are criminally underused, with only a happy few DMs daring to run those off-the-beaten-path creatures in a game session. Now that I'm finding more opportunities to be the DM, I have returned again to these hallowed pages, mining through them for interesting encounter possibilities. Turns out, though, that you have to take care not to bite off more than you (or your PCs) can chew.