The quiet guardian, perched in the trees
Understands the secrets of the breeze
"'Welcome!' the Elf then said again in the Common Language, speaking slowly. 'We seldom use any tongue but our own; for we dwell now in the heart of the forest, and do not willingly have dealings with any other folk. Even our own kindred in the North are sundered from us. But there are some of us still who go abroad for the gathering of news and the watching of our enemies, and they speakthe languages of other lands. I am one. Haldir is my name...'"
- Lord of the Rings: The Fellowship of the Ring by JRR Tolkien, chapter "Lothlorien," pages 444-45. Ballatine, seventy-second printing, April 1981
Very little is known of the Haldir of Lorien in Tolkien's Lord of the Rings trilogy. He is a southern Elf who lives in the Golden Wood of the Galadhrim, and is a subordinate of Lord Celeborn and Lady Galadriel. Haldir is a MarchWarden of the guards that protect the borders of Lothlorien. He is an excellent archer. Little is also known of his family... Only that he has two brothers who are also guardians of the Forest Lothlorien: Rumil and Orophin. Haldir served as a guide to the Fellowship in Lothlorien, both as they were entering the great forest, and again when they left it.
In the Hollywood movies directed by Peter Jackson, the role of Haldir was played by Craig Parker. He played a rather arrogant and cold Haldir who was not all too happy about allowing the Fellowship, bearing an evil ring, into his forest. He gained much fanfare for this somewhat lesser figure, however; especially after Jackson had him die at the battle of Helm's Deep in the second movie. This never happened in the books: there were no Elves at Helm's Deep.
Haldir remains popular through the films. Here's to our guardian of Lothlorien! ^_^
According to the appendices in the back of the third book, Return of the King of the Ballatine April 1981 printing, Haldir appears: I pg. 444-64, 479-81, and is mentioned on pg. 496. II, pg. 273. I'm guessing the last one was only a mention of him as well. So, go read up on your Haldir! ^_^