During Jefferson’s term first as minister plenipotentiary and later minister to France from 1784 to 1789, he acquired some 2,000 volumes while he was in Europe. Before he returned to America in 1789, he compiled a list of the books he had acquired while abroad, hence its name, the “1789 Catalog.” This manuscript catalog has also been referred to, particularly in Sowerby, as Jefferson’s “undated manuscript catalogue.”
This 1789 Catalog is a 50-page manuscript catalog in Jefferson’s own hand. Although undated, it was probably compiled by Jefferson around 1789, given the comprehensive list of acquisitions recorded which reflect most, if not all, of the titles he had purchased during this period of intense book acquisition overseas. The fewer occurrences of erasures and corrections relative to Jefferson’s 1783 Catalog (which was maintained over a period of some 40 years) suggests that this particular inventory list was made when this collection was quite fully formed.
When proposing to sell his library to Congress twenty-five years later, Jefferson reminisced about his bookbuying excursions in Paris during this period. In his letter to Samuel Harrison Smith dated 21 September 1814, Jefferson recalled,
“While residing in Paris I devoted every afternoon I was disengaged, for a summer or two, in examining all the principal bookstores, turning over every book with my own hands, and putting by every thing which related to America, and indeed whatever was rare & valuable in every science. besides this, I had standing orders, during the whole time I was in Europe, in it’s principal book-marts, particularly Amsterdam, Frankfort, Madrid and London, for such works relating to America as could be found in Paris.” 
This Catalog appears to include books Jefferson acquired either through purchase or gift. He recorded the prices of books he purchased, and these were most often denominated in French currency (livre tournois), as well as in English (pounds and shillings), or other European currency.
During his time abroad, Jefferson very likely had with him his 1783 Catalog which provided him with a list of the books he owned, as well as books he hoped to acquire. Sowerby wrote about the possibility that Jefferson did not take his 1783 Catalog with him to France, and so brought the 1783 Catalog up to date with his new acquisitions on his return from France.  However, this is highly unlikely given Jefferson’s preoccupation with his library, and the anticipated opportunities Europe would offer him in adding to it substantially.
There is a characteristic slash mark found at the beginning of each title in the 1789 Catalog, with the exception of titles that were crossed out. It is not known precisely what the meaning and significance of these slash marks were to Jefferson. One possible scenario is that beginning in early 1791 after returning from France in 1789, Jefferson utilizes his 1789 Catalog as a checklist while unpacking the 15 cases of his library books that had been shipped to him from Paris. As he unpacks his books and places them on his book shelves in Philadelphia, he checks off the titles in his 1789 Catalog. By that time Jefferson had taken up residence in Philadelphia as Secretary of State in George Washington’s cabinet.
Almost all of the titles found in the 1789 Catalog are also found in the 1783 Catalog. It is unclear whether Jefferson recorded his overseas acquisitions in his 1783 Catalog at the time of acquisition or while he was in Europe, or if he had the titles transferred from his 1789 Catalog after his return to America.
It is also probable that Jefferson included in the 1789 Catalog titles he acquired which he sent to friends. There were a number of book acquisitions that were recorded in the 1789 Catalog and subsequently crossed out by Jefferson, and were never recorded in his 1783 Catalog nor in the sale to Congress in 1815.
The 1789 Catalog is organized into chapters and has the same classification scheme as Jefferson’s 1783 Catalog. The only chapter heading that differs from the 1783 Catalog is the one used for Chapter 6. In the 1789 Catalog, Jefferson titled Chapter 6, “Cosmology.” In the 1783 Catalog, he titled the same chapter, “Natural Philosophy.”
The 1789 Catalog is at the Massachusetts Historical Society, and is part of the Coolidge Collection of Thomas Jefferson Manuscripts. These papers were presented to the Society in June 1898 by Thomas Jefferson Coolidge, great-grandson of Thomas Jefferson, and son of Jefferson's granddaughter Ellen Randolph Coolidge. It is a small, unbound volume (ii, 50 pages) with pages measuring 4 1/2 × 7 1/4 inches. It does not have a title page.
1. Thomas Jefferson to Samuel Harrison Smith, 21 Sept. 1814, Thomas Jefferson Papers, Manuscript Division, Library of Congress. Published in PTJ:RS, 7:681-684