There are many. Actors, publishers, other writers — most of those who wrote
their autobiographical memoirs who knew Clemens mention him. One method to
track these down is to do a google advanced book search. For “author” enter
the name of the person you suspect knew Twain, and then enter the phrase
“Mark Twain”. The search engine will return you the page numbers where his
name occurs within that author’s work.
On Sunday, June 30, 2019, Clay Shannon <[log in to unmask]> wrote:
> Are there any surviving writings about Twain by those who actually knew
> him, other than those by Susy, Clara, Howells, Katy Leary, Dorothy Quick
> (the Angelfish), and Paine?
> I would be especially interested in what the Clemens family themselves
> said/wrote about him (his mother and siblings) and the Moffett family; but
> also Harte, Goodman, Redpath, Keller, Kipling, Bixby, Howland, Paige,
> Twichell, Aldrich, Gilder, Joel C. Harris, &c &c.
> I do know that Kipling wrote about his "pilgrimage" to meet Twain.
> Do such writings exist? Even better would be if they were all collected
> together in a volume (excluding the writings which are already of book
> length - those alluded to in the first paragraph). Has anybody done this
> - B. Clay Shannon