by Arthur T. Hadley (1885; Johnson Reprint Corporation). This long-forgotten book is a gem, and its teachings are as applicable to today’s economy as they were to that of the late nineteenth century, when it was written. Hadley was a leading economist in his day (he later became president of Yale). He even discovered a flaw in the economic reasoning of David Ricardo, which must have been a satisfying moment. The book is clearly written and mercifully free of the ideologies of the day. And if you would like to understand why the airline business is so often one of feast or famine, with frequent price wars, Hadley will tell you exactly, because railroads and airlines operate with very similar economic constraints.