The Henshaw Reports were the reports of Clifford Henshaw and the records of his trans-Atlantic communication with Delphine Seydoux whom he was acting as the handler for in a secret mission.
History
During his work with Delphine Seydoux to retrieve the Hand of God from the Nazis, Men of Letters operative wrote the Henshaw Reports which were the reports on their mission. The reports contained copies of the Trans-Atlantic cables between Henshaw and Delphine and information on Gumprecht, her main target. They also talked about how Henshaw was able to get a Men of Letters contact in the OSS to requisition the USS Bluefin to carry Delphine and the Hand of God back to America.
At some point between 1943 and 1958, the Henshaw Reports were bound into a book that was kept in the library of the Men of Letters bunker.
In 2016, hunter and Men of Letters Legacy Sam Winchester learned of Delphine's mission and her connection to the Men of Letters from the Vichy Memorandems. Interested in finding the Hand of God to use as a weapon against the Darkness, the Winchesters search the bunker's archives and find the book with the Henshaw Reports. As they are in French, Sam uses his laptop to translate through the Internet, getting an 87% accurate translation. Using the Henshaw Reports and historical records regarding the Bluefin, the Winchesters decide to use time travel to go back to 1943 and get the Hand of God before the Bluefin is sunk.