The documentary that focuses on Natan Sharansky's experiences as a Soviet dissident is titled "Defending the Human Spirit". This film explores Sharansky's life, his struggle against the Soviet regime, and his eventual role in advocating for human rights. It highlights his imprisonment, his fight for freedom, and his contributions to the movement for dissidents in the Soviet Union.

If you're interested in more details about the documentary or Sharansky's life, feel free to ask!