When Samuel Langhorne Clemens died in 1910, the man the world knew as Mark Twain left behind an estate valued at $611,136. His property included $70,000 worth of real estate, more than $500,000 in personal property, and a $200,000 valuation for the Mark Twain Company, which owned the copyrights to his writings. At first glance, $611,136 may not sound earth-shattering. Adjusted by basic consumer inflation, Twain's estate works out to roughly $20 …