This writeup contains big fat spoilers for the Lord of the Rings

Saruman is a character that features in J.R.R Tolkien's Middle-Earth mythos, most famously the Lord of the Rings.

Saruman is actually a Maia, a sort of angelic spirit that entered Arda shortly after its creation. He dwelled in Valinor, in the west, and was known as Curumo.

About a thousand years into the Third Age of Middle-Earth, after the destruction of Numenor, the Istari began arriving in ships. Curumo was the first of the Istari (or wizards) on Middle-Earth. He took the shape of an old man dressed in white and hooded, and the name Saruman the White, or Curunír to the elves. He was the chief of the Istari.

When the White Council was formed in 2463, Saruman became its head, against the wishes of Galadriel. In 2759 he moved in to the tower of Orthanc in Isengard, after being given the key by the Steward of Minas Tirith. It was here that he discovered the palantír and began experimenting with it.

At some point Saruman was ensnared by the Enemy. Whether this happened before he helped the Council drive Sauron out of Dol Guldur (in 2941) or afterwards is unclear, but at some point his palantír must have linked with Sauron's, and he became an agent of -- and also a traitor to -- the Dark Lord.

After a secret and rapid militarisation of Isengard, Saruman trapped Gandalf in Orthanc and tried to capture the One Ring from Frodo Baggins. Over the years Saruman had become an expert on the Rings of Power, and had long suspected that Sauron's ring had survived. He sought to claim it for himself.

Saruman's army of men and Uruk-Hai (a particularly strong type of Orc) was defeated by the men of Rohan and the intervention of the Ents and Huorns. Saruman was stripped of his staff and his title by Gandalf, and trapped in Orthanc with his one-time spy Wormtongue. He escaped to cause trouble in the Shire, and was finally killed by Wormtongue on the 3rd of November 3019. Tolkien describes:

"...about the body of Saruman a grey mist gathered, and rising slowly to a great height like smoke from a fire, as a pale shrouded figure it loomed over the hill. For a moment it wavered, looking to the West; but out of the West came a cold wind, and it bent away, and with a sigh dissolved into nothing."1
Random Saruman facts:

dates given are of the Third Age of Middle Earth.
1 Lord of the Rings, book six.