The MS is divided into the following sections:

• ‘Diatribe du Docteur Akakia, médecin du Pape: décret de l’Inquisition; et rapport des professeurs de Rome au sujet d’un prétendu Président. Rome 1753.’
  
• ‘Berlin du 16eme Decembre 1752’
• ‘Decret de l’Inquisition de Rome’
• ‘Augement des Professeurs du Collége de la Sapience’
• ‘Mémoire’, written in the hand of Collini with an autograph correction by Voltaire
• ‘Reponse de Mr de Voltaire à Mr de Maupertuis’
• ‘Avertisement qui a paru dans les gazettes litteraires et ordinaires de Leipzig’

Reflected in the collection are his early years as a Swiss immigrant, his life on the Pennsylvania frontier, his service as a Senator and Congressman from that state from 1784 to 1801, his work as Secretary of the Treasury during 1801-1814, and his later career as a diplomat. There is also genealogical material on the Gallatin family, including source documents. Topics given coverage in the collection include Pennsylvania and United States politics, U.S. foreign policy and treaties, revolution in Geneva, roads and canals, land speculation, banking, tariff, Americans in Europe, Indian languages and affairs, U.S. expansion, the Northeastern boundary settlement, and the slave trade. Among the numerous correspondents found in the collection are John Quincy Adams, Jean Badollet, Susanne Gallatin-Vaudenet, Voltaire, Catherine Pictet, James W. Nicholson, Alexander Dallas, Thomas Worthington, Thomas Jefferson, James Madison, Tench Coxe, John Randolph, John Jacob Astor, James Monroe, Comte de Romanzoff, Lord Ashburton, Henry Clay, W.H. Crawford, Hannah Nicholson Gallatin, Marquis de Lafayette, Madame de Stael, G.W. Erving, Duc de Richelieu, Richard Rush, J.C. Hottingeur, John Forsyth, Etienne Denis de Pasquier, Baron Hyde de Neuville, French foreign minister Chateaubriand, Peter Stephen Du Ponceau, Nicholas Biddle, H.U. Addington, George Canning, David Gelston, Albert Rolaz Gallatin, David Shriver, Jr., A.R. Gallatin, and A.H. Gallatin.