Guinness World Records (GWR) is an anually-published reference book, containing information about world records and extremes, including both human achievements and natural records. The book itself holds a world record, since it is the best-selling copyrighted book of all time. In the United States, it is also one of the most frequently stolen books from public libraries.
For many decades, GWR has had a gerontology section, keeping track of the oldest people in the world.