Dr. Lecter does have information on Buffalo Bill, but he will not give it up before forcing Starling into a quid pro quo to get personal information from her. Much of the story's force comes from the relationship between Starling and Dr. Lecter. The desire to save Buffalo Bill's latest victim (who happens to be a powerful Senator's daughter) makes the situation urgent for the FBI. But Dr. Lecter has all the time in the world.
Both the book and movie are smart and scary. The book provides a little more detail and background. But the parts changed or left out of the movie mostly made it better.
The movie won several Academy Awards, including all of the top five categories: Best Picture, Best Actor for Anthony Hopkins, Best Actress for Jodie Foster, Best Director for Jonathan Demme, and Best Adapted Screenplay.
This is one of my top favorite movies of all time. Check out the movie and book here: