Well, I started with the "new" red box, but this is a marvel of classic D&D, as it provides insight into everything a campaign needs - and the scan is truly astounding!
A really - well nice is the wrong term, let's stick to horrible - set of undead creatures you might encounter in your next dungeon.
And as you get the raw graphic as a bonus, you can pull out as many hordes as you like - if you need to...