In the 1930s, automobiles promised a new measure of mobility for America's middle class. But in the era of segregation, the open road was anything but open for black motorists. Finding a mechanic, restaurant or hotel on a long car trip could be difficult or even dangerous.

In 1936, a Harlem postal worker named Victor Green published the first edition of a resource that would guide black travelers to welcoming destinations. The Negro Motorist Green Book (later retitled, and also known simply as the "Green Book") listed black-owned and black-friendly businesses in the New York City metropolitan area. In the years that followed, the Green Book quickly grew into a national and even international guide, aided by tips from readers and Green's fellows postal workers around the country.

Last month, the New York Public Library's Schomburg Center for Research in Black Culture posted high-resolution scans of almost every edition of the Green Book online for public use.

Brian Foo of NYPL Labs also offered a different view with Navigating the Green Book, a project that maps locations from the 1947 and 1956 editions (data for 1956 came from the University of South Carolina, which has a map of its own). You can browse locations or use a virtual trip planner to generate a hypothetical itinerary using locations from the book.

Few of the New York City locations listed in the book are still around. Out of 42 hotels, bars and restaurants in the 1962 edition, most have disappeared completely. Boulevard Restaurant in Jamaica has been replaced by a medical supply store. The site of the Lincoln Terrace Hotel in Crown Heights is now a charter school. Only the Hotel Edison near Times Square still exists under the same name in the same location.

Later editions of the book openly discussed segregation and civil rights issues. In the introduction to the 1948 edition, Green wrote:

There will be a day sometime in the near future when this guide will not have to be published. That is when we as a race will have equal opportunities and privileges in the United States. It will be a great day for us to suspend this publication for then we can go wherever we please, and without embarrassment.

Green passed away in 1960. The last edition of the book was published in 1966, two years after the passage of the Civil Rights Act.