I have just added the complete text of W. D. Howells, _My Mark Twain_
(New York: Harper & Brothers, 1910), to my Twain site.  It is at:

http://marktwain.miningco.com/library/texts/bl_wdh_mmt_contents.htm

For anyone not familiar with the book, it includes both memoirs and
criticism.  The full contents are:

Part First - Memories

     My Mark Twain

Part Second - Criticisms

     Introduction
     The Innocents Abroad
     Roughing It
     The Play from The Gilded Age
     Mark Twain's Sketches, Old and New
     The Adventures of Tom Sawyer
     A Tramp Abroad
     Mark Twain
     A Connecticut Yankee in King Arthur's Court
     Joan of Arc
     Review of an Italian's Views of Mark Twain
     Mark Twain: An Inquiry
     The American Joke

The online text is divided by chapter, and on the contents page I
have listed the individual chapters of the biographical section with
brief annotations about what each one is about.  I hope these will
make it easier to find specific information.  The entire site is also
searchable.

Jim Zwick