Hi, Alex. The "friend and fisherman" who hosted Mark Twain (and his daughter Jean) during the late summer of 1902 was Millard Sewell. That happened to be a critical moment for the family, and I presented a short paper that touched on some of the circumstances at the last Mark Twain conference in Elmira. It was supposed to have been published in the Mark Twain Journal, but for some reason that never happened. However, you can find a version on my website at http://salwenpr.com/clemensletters_article.pdf. The "admirable story" that Twain "spilt" onto the page that summer (48,000 words in six weeks, by his reckoning) was a lurid tale of murder and blackmail, apparently based at least partly on a real event he had heard about on his recent sentimental visit to Hannibal, Missouri, Twain's long-ago boyhood home. It was never finished, but it was published under the title "Which Was It?" in the 1968 collection "Which Was the Dream?" Peter Salwen