The Benjamin Franklin Butler Notebook consists of a handwritten, bound manuscript providing a book-length, vehement critique of the military leadership and personal character of General Ulysses S. Grant. Though attributed to Benjamin Franklin Butler, a closer inspection in 2009 suggested a different author, possibly former Union Brigadier General Gustave Paul Cluseret.

The author repeatedly charges Grant with gross incompetence, recklessness, bloodthirstiness, self-promotion, favoritism, and cowardice. Supporting his claims with a number of clippings from newspapers, official records, and Grant's own reports, the author vilifies Grant's character and abilities as a military commander, while at the same time defending the actions and reputations of several of Grant's lieutenants, including Benjamin Butler, William Rosecrans, and Franz Sigel. Particularly damning is the author's assessment of the Battle of the Crater ("a master-piece of imbecility") at Petersburg.

Though several of the clippings date from 1865, the tone of the item suggests that it was written prior to the war's conclusion. The manuscript seems to be only a fragment of a larger work, as the text has no definite conclusion and commences well into the second chapter. The first chapter heading within the book is "Chapter 3: Shenanndoah [sic] Valley, Sigel and Hunter's Army." Succeeding chapter titles are: "Second Part of the Campaign of the Army of the Potomac," "Part 3rd of the Campaign of the Army of the Potomac," "Sherman," "Wilmington Expedition," "Sherman's Campaign from Savannah to North Carolina," and "Movements Preparatory to the Definitive Action of the Army of the Potomac Against Richmond." Accompanying the manuscript is a complete, typed transcript, and a twentieth-century photographic reproduction of an image of Benjamin Butler.