It's made of aluminum, and the first half of this video shows some of the production tools involved in the extrusion, milling and laser etching. It may be a MacBook, but we're suckers for behind the scenes production vids like this, follow the link to see for yourself. WARNING: Excessively smug Apple marketing people patting themselves on their backs and "inspirational" backgound music aplenty. Cheese factor 11.
1. The Apple MacBook Finished Product
2. The machined aluminum "Unibody" of the notebook. (Incidently, milling out a solid block is a ridiculously expensive method, both in terms of time and energy. Milling a pre-cast frame is much more efficient from a materials, time, and energy utilized perspective.)
3. Milling, laser cutting, laser etching, surface treatments, etc.
4. The sum of its parts.