John Moody was an American financial analyst, businessman and investor. He pioneered the rating of bonds and founded Moody's Investors Service. Moody's Manuals are still issued, carrying on the tradition begun by Moody's Manual of Railroads and Corporation Securities and continued by the annual Moody's Analyses of Investments.
Librarian note: There is more than one author in the Goodreads database with this name.
An interesting history of the major US railroads until 1918. Great if you're interested in a survey of the men and companies that built the American railroad system.
Be warned: some exceptionally racist quotes from the time presented matter-of-factly -- an off-putting but accurate reflection of that time in American history.