The word "eminent" is used to describe people in a high station, for those who are famous, well-known or held in esteem. When you change this description to "preeminent", the person would need to be considered of the highest station, or considered the most famous or most well-known one in his field. For example, there have been many eminent doctors in Canada. However, a doctor who might be considered preeminent is Sir Frederick Banting. He made one of the most important medical discoveries of the 20th century with his use of insulin for diabetes. Hope this helps

They're surprisingly different. "Eminent" is usually applied to people. It is a somewhat formal, dignified, and rather old-fashioned word. It is often applied to people in a profession: the "eminent professor," "eminent doctor," "eminent statesman," etc. "Walter Lippman was an eminent journalist." "The eminent conductor, Leopold Stokowski, was famous for his orchestral arrangements of pieces by Bach." "Preeminent" means "well above all others," "head-and-shoulders above others," "in a class of their own." It is stronger than just saying "best." It means "easily the best." It means better than the rest by a large amount. It can be applied to people or to institutions. "Rhode Island School of Design is the preeminent design school in the United States." "Jane Goodall is the preeminent authority on chimpanzees."