A Fortune excerpt from Adam Lashinsky's upcoming Inside Apple book details some of the extreme security measures the company takes to keep products secret and build up hype. The company will, for instance, sometimes even rely on construction, changing spaces in its offices to include new walls, doors, or frosted windows. Some areas, known as "lockdown" rooms, will have no windows at all, and be so heavily restricted that no information goes in or out unless absolutely necessary.
