The Guinness Book of Records (or in recent editions Guinness World Records, and in previous US editions Guinness Book of World Records) is a reference book published annually, containing an internationally recognized collection of world records, both human achievements and the extrema of the natural world.
The first edition was published in 1955, commissioned by the Guinness brewery after a debate in a pub over the fastest species of gamebird could not be settled with existing reference books. It was researched by Ross and Norris McWhirter, twins and noted British athletes and journalists, who at the time ran a fact-finding agency in London. When the book became a surprise hit, many further editions were printed, eventually settling into a pattern of one revision each year, published in October to coincide with Christmas sales. The McWhirters continued to publish it and related books for many years. Norris had an encyclopedic memory - on the TV series Record Breakers, based upon the book, he would take questions posed by children in the audience on various world records and would usually be able to give the correct answer—the feature being called 'Norris on the Spot'.
Recent editions have focused on record feats by human competitors. Competitions range from obvious ones such as weightlifting to the more entertaining ones such as longest egg-throwing distance or the number of hot dogs that can be consumed in 10 minutes - although eating contest style entries are no longer accepted, possibly for fear of litigation. Besides records about competitions, it contains such facts as the height of the tallest human (Robert Pershing Wadlow), the heaviest tumour, the most poisonous plant, the world's shortest river (the Roe River), the longest-running drama (Guiding Light), etc.
Each edition contains a subset of the larger set of records in the Guinness database, and the choice reflects the year of publication. In recent years, many records devoted to current pop culture trends have been added.
The Guinness Book of Records is the world's most sold copyright book, thus earning it an entry within its own pages. A number of spinoff books and television series have also been produced.
Several world records that were once included in the Guinness Book now are not, for ethical reasons. By publishing world records in a category, the Guinness Book may encourage others to try to beat that record, even at the expense of their own health and safety. For example, following publication of a "heaviest cat" record, many cat owners overfed their pets beyond the bounds of what was healthy. Therefore, entries such as these were removed. Likewise, other records related to dangerous stunts are often not published, for example those closely related to freediving. Other records, such as sword swallowing, have been closed to further entry due to the fact that the current holders have performed beyond what is considered safe human tolerences.