Although pervasive racial discrimination and poverty limited black car ownership, the emerging African-American middle class bought automobiles as soon as they could, but faced a variety of dangers and inconveniences along the road, from refusal of food and lodging to arbitrary arrest.
African-American travelers faced hardships such as white-owned businesses refusing to serve them or repair their vehicles, being refused accommodation or food by white-owned hotels, and threats of physical violence and forcible expulsion from whites-only "sundown towns".
Green founded and published the Green Book to avoid such problems, compiling resources "to give the Negro traveler information that will keep him from running into difficulties, embarrassments and to make his trip more enjoyable." From a New York-focused first edition published in 1936, Green expanded the work to cover much of North America, including most of the United States and parts of Canada, Mexico, the Caribbean, and Bermuda.
By the late afternoon, "it casts a shadow of apprehension on our hearts and sours us a little. One alternative, if it was available, was to arrange in advance to sleep at the homes of black friends in towns or cities along their route.
However, this meant detours and an abandonment of the spontaneity that for many was a key attraction of motoring.
The Negro Motorist Green Book (at times styled The Negro Motorist Green-Book or titled The Negro Travelers' Green Book) was an annual guidebook for African-American roadtrippers, commonly referred to simply as the Green Book.