This document is the SEC Form 10-K annual report filed by USG Corporation for the fiscal year ending December 31, 2003. It provides information on USG's business operations, organized into three segments: North American Gypsum, Worldwide Ceilings, and Building Products Distribution. Key details include that USG filed for Chapter 11 bankruptcy protection in 2001 to address asbestos liabilities, and is the largest gypsum wallboard manufacturer in the US and other countries.