_Is Shakespeare Dead?_ is the place to look. According to _M.T. A-Z_,
"Ostensibly an essay arguing that William Shakespeare could not have
written the plays attributed to him" (247)
I don't know anything about lectures on the subject. Perhaps the reporter
was thinking of Twain's _Is Shakespeare Dead?_ chapter 1 statement that he
used to argue the point with steamboat pilot George Ealer. (248)
Our local PBS affiliate, in March, (on Frontline, I think) did a
who-was-really-Shakespeare piece which spent a lot of time on Twain's
theory.
Take a look in the Forum Archives for David Tomlinson's 15 Feb. 1995
review of Anthony Berret's _Mark Twain and Shakespeare_.
larry marshburne