The context for the value of the Melish map is what constitutes profound historical importance in the body of published works on this subject. Again and again this is what collectors are turning to as the primary gauge of desirability and value.
The best essay still is what Walter Ristow wrote about the Melish map for the Library of Congress Quarterly Journal in September 1962. It is one of the three cornerstone maps of the United States that the Library of Congress has focused on studying intensely for over 80 years! The others are the Mitchell and the Distrunell. Will send along all three essays to you now.
The context is that all of the maps being offered to you made history and showed considerable improvements over existing knowledge but none were on such a broad level as the John Melish. Again and again the leading scholars - Col. Martin, Walter Ristow, Seymour Schwartz, Ralph Ehernberg and many others come back to these maps as the ones that had the profound influence.
The Winslow-Brooke-Thomas maps of the Potomac River also are in this group but are the original manuscripts which is amazing. Nothing of this importance has ever come on the market. They transcend historical importance because they actually changed history simply because settlers heard they were being made and moved to live in the Northern Virginia.
For 1/4th of what a fine Old Master painting sold for yesterday at Sothebys you could have a collection that inlcuding all of these maps.