By Brandy McDonnellA version of this story appears in the Sunday Life section of The Oklahoman.The producer: 'Les Miserables,' 'Phantom of the Opera's' Cameron Mackintosh shares secrets of his successThere’s nothing basic about the career Sir Cameron Mackintosh, who over the past half-century has become widely regarded as the most successful theater producer in the world.Looking back, though, the legendary impresario said he sees something basic in how he chose so many successful shows.“It’s very interesting going over my career now, which is over 50 years, nearly every single musical that I’ve done has been based on an existing classic, whether it be a book or a film or occasionally a play.Read more on NewsOK.com