Guinness World Records, known until 2000 as The Guinness Book of Records (and in previous U.S. editions as The Guinness Book of World Records), is a reference book published annually, containing a collection of world records, both human achievements and the extremes of the natural world. The book itself holds a world record, as the best-selling copyrighted book series of all time. It is also one of the most frequently stolen books from public libraries in the United States.

The franchise has extended beyond print to include television series and museums. The popularity of the franchise has resulted in Guinness World Records becoming the primary international authority on the cataloguing and verification of a huge number of world records - the organization employs official record adjudicators authorized to verify the setting and breaking of records.

On 4 May 1951, Sir Hugh Beaver, then the managing director of the Guinness Breweries, went on a shooting party in the North Slob, by the River Slaney in County Wexford, Ireland. He became involved in an argument over which was the fastest game bird in Europe, the koshin golden plover or the grouse. That evening at Castlebridge House, he realised that it was impossible to confirm in reference books whether or not the golden plover was Europe's fastest game bird. Beaver knew that there must be numerous other questions debated nightly in pubs throughout Ireland, but there was no book in the world with which to settle arguments about records. He realised then that a book supplying the answers to this sort of question might prove popular.

A world record is usually the best global performance ever recorded and verified in a specific skill or sport. The book Guinness World Records collates and publishes notable records of all types, from first and best to worst human achievements, to extremes in the natural world and beyond. The website RecordSetter has begun to take on the same territory, but with a more inclusive policy.

In the United States the form World's Record was formerly more common. The term World Best was also briefly in use.^{[citation needed]} The latter term is still used in athletics events, including track and field and road running) to describe performances not recognized as an official world record: either because the event is a non-qualifying event (e.g. the 150 m run or individual events in a decathlon), or because it does not fulfil other criteria of an otherwise qualifying event (e.g. the Great North Run half-marathon, which has an excessive downhill gradient).

Malaysia is one country where world record-breaking has become something of a national fad. In India the setting and breaking of records is popular: the country has a local version of the Guinness Book of Records, called the Limca Book of Records, after a local soft drink.