The Elves are one of the fictional races that appear in the work of J. R. R. Tolkien. Their complex history is described in full only in The Silmarillion, and it is mentioned tangentially in The Lord of the Rings. Elves were the first inhabitants of Middle-earth who were able to speak. They are sometimes called the Firstborn (as opposed to Men, the Afterborn). The Elves named themselves Quendi (the Speakers), in honor of the fact that, when they were created, they were the only living things able to speak. (This name is no accident - Tolkien was a linguist.) Oromë called them Eldar (Star People) because they were born under the stars, but the name is generally considered to exclude the Avari.
Elves are described as the fairest of all creatures in Middle-earth, lovers of art (particularly songs, which they sing in beautiful voices). Elves are also stronger than Men and have far sharper senses, enabling them to communicate and be in harmony with nature. Elves possess an affinity with nature and the earth that Men may see as "magic." Their memories and dreams are as vivid as real life. Their unusually keen eyesight enhances their proficiency with bows and arrows during battle.
Tolkien saw Elves as human beings prior to the original sin; while this made them perfect (it is specifically told that not a single Elf joined Morgoth or Sauron, the Enemies), it also made them less able than the mortal Men, that appeared after them. By the Third Age (the time of The Lord of the Rings), the importance of Elves in affairs of the world is diminishing, and only a few of them are left in Rivendell, Lothlórien, and the Mirkwood. Many of them can be seen walking west, towards the elf havens, to leave Middle-earth forever, and those who stay in the meanwhile know that it is their fate to "diminish and go West". None of them are to remain in Middle-earth after the end of the Fourth Age.
Some important Elves:Half-elven: Sundering of the Elves, Elvish language