Idlewild, Michigan was once known as “The Black Eden”—a resort where black writers, business people, physicians and entertainers spent their summers in a racially segregated country. In its earliest days, you could run into W.E.B. Du Bois; in its later years, you could catch an Aretha Franklin show. But it wasn’t the only such spot. Even before the Negro Motorist Green-Book came out in 1936, resorts had opened up all over the country catering to black vacationers.