The document discusses the importance of documentation for system analysis. It states that documentation is used to communicate information about a system and track its progress. It then lists several uses of documentation, including facilitating communication, training new users, troubleshooting, evaluation, and quantifying financial impacts. The document also discusses methods of documentation and notes that the basic importance is to learn from past experiences to improve future evaluations and modifications. It concludes that documentation is an important but often ignored part of the system development life cycle.