Is Hannibal based on the Thomas Harris novels? Are we starting at the beginning, covering the same ground as the movie Manhunter?
It's set in the Thomas Harris universe, but it's set during the time before the first novel,
Red Dragon, in the events prior to Dr Lecter's capture. In these first two seasons so far, Lecter is a psychologist, therapist, and a consultant/profiler on various ongoing homicide investigations. It's partly procedural, in that there are several murder cases or serial killers that are investigated that make up the meat of the episodes, perhaps spanning one or more episodes, with the blossoming relationship between Lector and criminal profiler Will Graham being the story thread that ties the episodes together.
The showrunners definitely plan on adapting the novels. I presume the third season will be the events of
Red Dragon, since they've just about expended the window of time before that as we approach the end of season 2. They will adapt
The Silence of the Lambs, and
Hannibal (the novel), perhaps even run on beyond what Harris has written.