Jean-Baptiste Grenouille is the main character. He is an odd anti-hero who does not have an "odor" himself, but he *can* smell and is obsessed with odors and through a series of experimentation, is first able to create scents that dominate other people, then actually acquires the ability to "steal" the odors of others.
The "message" of Siskind's novel is perhaps not to admire people so much that you are blinded to their ulterior purposes. At first, the people respect and are awed by Grenouille's abilities, but he is proven to be a monster. The author seems to be arguing for the necessity of social and moral restraints.