Dr. Liet Kynes (portrayed by Max von Sydow) was a minor character in the sci-fi film Dune. He was an imperial planetologist in service to Padishah Emperor Shaddam Corrino IV, though he was also secretly a Fremen leader. When House Atreides took control of the Arrakis fief, Duke Leto had high hopes of gaining Kynes' trust and the support of the Fremen. Kynes instructed the Duke in the use of the stillsuits that were essential to survival on Arrakis and was impressed by the Duke's concern for his spice miners over the spice itself when a harvester was attacked by a giant sandworm.
After House Harkonnen launched their invasion of Arrakeen and defeated House Atreides, Rabban tore open Dr. Kyne's stillsuit. He then ordered his men to take the doctor out into the desert where, without an intact stillsuit, he would die of dehydration.
Trivia
Dr. Kynes' first name is not made apparent in the film, though in Frank Herbert's novel it is made clear that Kynes is the father of Chani, the Fremen woman who becomes Paul Atreides' concubine. In the film, while Chani introduces herself to Paul as "Daughter of Liet", it is unclear to those unfamiliar with the novel that she is referring to Dr. Kynes.