Later in life, Twain suggested that _The Gilded Age_ is really two books
that inadvertently occupy the same binding, but at the time of
publication he said that he and Warner collaborated substantially.  I think
we should pay at least as much attention to Twain's assertion that the book
is a full collaboration as to his later disavowal.  When the two were
writing the book, they agreed about the book's purposes and arguments, and
while they may have drawn on their own experiences to create particular
characters and each began one of the two main plots, over the course of
composition, the boundaries blurred, and they asked for advice from their
wives, too.

It didn't take long after the publication of _GA_ for Twain to outgrown
Warner as a mentor; it also didn't take him long to push Warner out of any
share of the profits from the Colonel Sellers play.  Twain, then,had good
reasons to downplay the significance and extent of the collaboration.  But
if we are to see how Twain grew, it is useful to see how much he agreed
with Warner in the early 1870s.   In other words, it's not useful to read
the sections that Twain drafted as if they were somehow pure Twain,
untouched by Warner.

Gregg