Context: NARA also maintains the Presidential Library system, a nationwide network of libraries for preserving and making available the documents of U.S. presidents since Herbert Hoover. The Presidential Libraries include:

Question: What agency maintains the Presidential Library system?
Answer: NARA

Question: What is the system that preserves the documents of US Presidents?
Answer: Presidential Library system

Question: Who is the earliest President that is represented in the archives of the Presidential Library system?
Answer: Herbert Hoover

Question: In what area of the US can one find the Presidential Library system libraries?
Answer: nationwide

Question: What did Herbert Hoover maintain?
Answer: Unanswerable

Question: What is the system that Herbert Hoover founded?
Answer: Unanswerable

Question: Where did Herbert Hoover spend much of his time?
Answer: Unanswerable

Question: What organization was started by Hoover for document storage?
Answer: Unanswerable

Question: Why did NARA create the Presidential Library System?
Answer: Unanswerable