Obi-Wan Kenobi is Luke Skywalker's mentor in the Star Wars Original Trilogy and Anakin Skywalker's master in the Star Wars Prequel Trilogy. As a Jedi, he embodies the ideals of the Prequel-era Jedi Order: cautious, focused, and very traditional. These aspects of his personality often put him in conflict with his unorthodox master, Qui-Gon Jinn, and his rebellious apprentice.
Obi-Wan Kenobi Before the Star Wars Films
Obi-Wan Kenobi was born on an unknown planet in 57 BBY. Like most Jedi, he was taken from his family at a very young age and brought to the Jedi Temple for training. For a while, however, it seemed that his chances of becoming a Jedi were slim; at the age of 13, he was sent to the Agricultural Corps, the destination for Force-sensitives who weren't chosen as Padawans.
On his way to the AgriCorps, however, Obi-Wan found a mentor in Qui-Gon Jinn. Because Qui-Gon's former apprentice, Xanatos, had turned to the dark side, the Jedi Master was at first hesitant to take Obi-Wan as a Padawan; but he soon realized Obi-Wan's Force potential and helped him develop into a powerful Jedi.
Obi-Wan Kenobi in the Star Wars Prequels
Obi-Wan avenged Qui-Gon's death after he was killed in a duel with Darth Maul; the fight earned him the rank of Jedi Knight. Although he did not share his master's opinion that Anakin Skywalker was the Chosen One of Jedi Prophecy, Obi-Wan wanted to honor Qui-Gon's wishes to train the boy. Despite the Jedi Council's disapproval, Obi-Wan accepted Anakin as his Padawan.
Ten years later, Obi-Wan's investigation of an assassination attempt on Padmé Amidala led him to Kamino, where cloners had created a vast army at the secret request of a Jedi Master. Obi-Wan's discovery occurred just in time for the clones to assist the Republic in fighting the Separatists, led by the Sith Lord Count Dooku. In the subsequent Clone Wars, the Jedi became leaders of the Clone Army. Obi-Wan became General Kenobi and earned the rank of Jedi Master, as well as a seat on the Jedi Council.
The Clone Wars led to dark times for the Jedi. While Obi-Wan hunted down General Grievous, the cyborg Separatist leader, his former Padawan Anakin turned to the Dark Side. Chancellor Palpatine, who was secretly a Sith Lord, ordered the clones to turn on their Jedi leaders with Order 66; Obi-Wan and Yoda were among the few Jedi who escaped. When he realized what had happened, and that Anakin had set a trap for the remaining Jedi, he attempted to warn them away with a beacon.
Obi-Wan faced Anakin in a duel, but could not kill him. Palpatine rescued Anakin, who was missing several limbs and badly burned. Surviving within the confines of a protective suit, Anakin became the Sith Lord Darth Vader. With the help of Yoda and Senator Bail Organa of Alderaan, Obi-Wan hid the newborn twin children of Anakin and his wife, Padmé. Organa adopted Leia, while Obi-Wan took Luke to Tatooine, Anakin's homeworld, and gave him to Anakin's stepbrother Owen to raise.
Obi-Wan During the Dark Times
During the Dark Times -- the time of the Empire, when the remaining few Jedi were being hunted down -- Obi-Wan hid on Tatooine and watched over Luke. He created a new identity for himself: the strange old hermit, Ben Kenobi. During this time, he received guidance from the ghost of his former master, Qui-Gon Jinn.
For a time, Obi-Wan believed that he and Yoda were the only survivors of Order 66. After a year in exile, however, he learned that Ferus Olin, a former Padawan who had left the Jedi Order, was still alive. While training Ferus, Obi-Wan was surprised to discover that even more Jedi had survived.