This informative book;" Collecting Historical Documents" by Todd M. Axelrod is an excellent guide to owning historical documents. Historical documents are collectibles. they are either one of a kind or have highly limited editions. These documents are unique in content and precious in quality.
Even though the book was published 34 years ago, it still has a lot of pertinent information, most especially all the examples of beautifully framed historical documents and photos. Mr. Axelrod is very knowledgeable about document collections, most especially autographs. He gives good advice pertaining to dealers and auction. Of special interest to me was chapter 4, "Maintaining Your Collection."