Elves were about six feet tall; taller than men. They tended to be slender, and they were very strong, and therefore could withstand all of the extremes of nature, from the coldest winters to the hottest summers. They did not sleep, but rather rested their minds in "waking dreams," or by staring at beautiful things. Most Elves were fair of complexion and had blonde hair, and none had beards. They are believed to have had somewhat pointed ears. Elves could die only by a horrible wound or by grief, and would otherwise live forever. The Eldar, and it is thought that the Elves of Middle-earth, could communicate without speaking. They were good by nature, and would only turn evil if they did not realize that what they were doing was evil, and if they felt it just and right.
The Elves had many great accomplishments, both peaceful and warlike. Their most celebrated peaceful accomplishment was the teaching of the ents to speak. Their most famous warlike accomplishments include the sending of Legolas with the Fellowship of the Ring, and the leadership of Elrond Halfelven in the Last Alliance of Men and Elves, and his founding of Rivendell, the last homely house east of the Bruinen (Loudwater), in 1697 of the second age.
The Elves were the most beautiful and the fairest of all earthly creautes, and they were similar to the Ainur, the creators of Middle-earth under Ilúvatar, in spirit. They loved all things natural to the earth, such as flowers and trees, but above all things Elves loved the water. They built great ships which they used to sail upon the ocean. They also greatly loved the stars in the night sky. The Elves had a curiosity about things of this planet greater than any of the other races. Thus they were also far more intelligent than any of the other speaking races of Middle-earth, save perhaps the Ents.
When men first entered into Middle-earth, the Elves welcomed them as peers or as friends. However, after the Fifth Battle of Beleriand in the First Age, men and Elves separated and became estranged. Only the first men, the Edain, maintained friendship with the Elves. Dwarves and Elves have been enemies since near the end of the First Age, when the Dwarves stole an elven jewel and then destroyed the city of Doriath, the most fair of all the cities in the World, save only Gondolin.
In the beginning of the First Age the Valar, the Ainur that dwelt upon earth, summoned the Elves over the Western Sea, at which point the race was divided into two distinct groups, the Eldar and the Dark Elves, or the Avari. The Eldar were those that sailed over the sea, and the Avari stayed upon Middle-earth. Only the Noldor did not remain in Valinor over the sea. The Elves were numerous in the First Age, and equally so in the Second Age, but by the Third Age they were fading, and in the Fourth Age, the Age of Men and the age we live in, Elves were and are gone altogether.
*The two trees were the original source of light for the world; consturcted by the Valar.