English: The Green Book was a travel guide published between 1936 and 1966 that listed hotels, restaurants, bars, gas stations, etc. where Black travelers would be welcome.
21 volumes, 1937 - 1964. According to legal research done by NYPL staff, those 21 volumes have no known US copyright restrictions, and can be used and reused freely.
Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (70 years p.m.a.), Mainland China (50 years p.m.a., not Hong Kong or Macao), Germany (70 years p.m.a.), Mexico (100 years p.m.a.), Switzerland (70 years p.m.a.), and other countries with individual treaties.