Along with many more of his private papers, it was found in the 1920s at Malahide Castle in Ireland, and was first published in 1950, in an edition by Frederick A. Pottle.
In it, Boswell, then a young Scotsman of 22, visits London for his second time.
One of the most notable events in the journal is Boswell's meeting on 16 May, 1763 Samuel Johnson, the famous writer, moralist, and lexicographer with whom Boswell would form a close relationship, eventually writing the biography The Life of Samuel Johnson.
The journal relates with much detail and candour his frequent and casual use of prostitutes.
I have for some days observed the symptoms of disease, but was unwilling to believe you so very ungenerous.
I was with my surgeon this morning, who declared I had got a strong infection, and that she from whom I had it could not be ignorant of it.
Madam, such a thing in this case is worse than from a woman of the town, as from her you may expect it.
I appeal to GOD Almighty that I am speaking true; and for these six months I have had to do with no man but yourself.
[1] The London Journal was but one of various journals written by Boswell, now gathered into a number of published volumes, but it is the only one whose material had not undergone extensive familial expurgation in the 19th century, and so it retained the racy material that made the London Journal an astonishing best seller on its publication.
Fundamentally an "academic book," it sold over a million copies when it appeared as the first of the Yale Boswell publications in 1950.