In 1799, a few years after Burns had died, "Auld Lang Syne" as we know it appeared in print for the first time. While the words had already been published with a different tune, and the tune had been published with different words, it was George Thomson, an Edinburgh-based music seller and amateur musician, who finally brought them together in his Select Collection of Original Scotish Airs, a major compilation to which Burns contributed countless songs. Thomson claimed (on the left-hand page) that his source was "an old MS. in the editor's possession," when in fact Burns had sent him the text just a few years before. In later editions, Thomson dropped the misleading word old.
"Should Auld Acquaintance Be Forgot", A Select Collection of Original Scotish Airs for the Voice, London: printed & sold by Preston; sold also by the proprietor G[eorge] Thomson, Edinburgh, 1799