The parchment-like skin is much like the skin of an Onion.

http://en.wikipedia.org/wiki/Garlic

The parchment-like skin is much like the skin of an onion, and is typically removed before using in raw or cooked form. An alternative is to cut the top off the bulb, coat the cloves by dribbling olive oil (or other oil-based seasoning) over them, and roast them in an oven.