Who is Dr. Sarton from The Caves of Steel and what is their importance?

Dr. Sarton is a citizen of the planet Aurora and a resident of Spacetown. He is the murder victim. He specialized in robotics and was the creator of Daneel. Dr. Sarton's goal was to understand the psychology of the Earthman in order allow Spacetown to succeed in the future. He possessed no immunity to Earth's many bacterias and could easily die from a common cold. This was his reasoning for creating Daneel, in order to be able to finish his research from within the City using a robot.