Tripe is the meat from the stomach linings of a ruminant. One of the fun things about ruminants is that they have multiple stomaches. Each of these stomachs, and therefore stomach linings, have different properties. Foodwise, tripe usually falls into one of four categories:
Smooth tripe, AKA plain tripe, flat tripe, gras double or blanket tripe comes from the first stomach, and is usually considered the worst type of tripe.
Honeycomb tripe comes from the second stomach, and is considered the best tripe. It is both meaty and tender.
Pocket tripe comes from the lower part of the second stomach.
Book tripe, AKA bible tripe or leaf tripe comes from the third stomach, and falls between smooth tripe and honeycomb tripe in quality.
Some ruminants have a fourth stomach, but as far as I can find, it doesn't produce usable tripe.
All types of tripe are tough, and are usually cooked for a couple hours before eating. These days, tripe you buy in stores is usually bleached and partly cooked already, to save time. In Western countries, most tripe comes from cattle. Slang to the contrary, tripe is supposed to be very tasty, although somewhat hard to digest.
A short list of tripe recipes:
Tripes a la mode de Caen (all four types of tripe!)
If you have more to add, /msg me.