In the 1920s a great part of Boswell's private papers, including intimate journals for much of his life, were discovered at Malahide Castle, north of Dublin. These provide a hugely revealing insight into the life and thoughts of the man. They were sold to the American collector Ralph H. Isham and have since passed to Yale University, which has published popular and scholarly editions of his journals and correspondence. A second cache was discovered soon after and also purchased by Isham. A substantially longer edition of "The Journal of a Tour to the Hebrides" was published in 1936 based on his original manuscript, edited by L. F. Powell. His "London Journal 1762–63", the first of the Yale journal publications, appeared in 1950. The last popular edition, "The Great Biographer, 1789–1795", was published in 1989. Publication of the research edition of Boswell's journals and letters, each including never before published material, is ongoing.