In the mid-70’s a new kind of pop music came on the scene that was pretty divisive. Whether you loved or hated it, 40 years ago, the first disco songs were making a splash on the dance floor, on radio, and in even in the movies with “Saturday Night Fever.” Disco made near-instant stars of many of its performers, but in many cases their fame was fleeting. Author James Arena has written a new book called “First Legends of Disco,” that features interviews with 40 disco stars looking back on their careers.