The Lord of the Rings is probably one of the least likely fantasy series to actually require an introduction, but for those few people out there who may not be aware of the series:

The Lord of the Rings is an epic High Fantasy series of novels written by the late JRR Tolkien. The story is a sequel to Tolkiens earlier work, written primarily for young adults, The Hobbit. Although a trilogy, Tolkien originally intended the work to be one large volume, but was pursuaded by publishers into splitting the story into 3 volumes.

It has since been reprinted countless times and translated into many different languages, becoming one of the most popular and influential works in 20th-century literature.