I'm not sure if it's extremely popular. It might be well - known within certain circles of readers who are into that genre, but it may not have mainstream popularity.
I'm not sure specifically as I haven't read it. But generally, a novel with such a title might be about a powerful figure in the underworld world. It could involve things like power struggles, crime empires, and the character's journey to become or maintain his status as the 'king' in that dark and dangerous realm.
Another option is to check with your local library. Libraries have a diverse selection of books. They can either have it on their shelves or they might be able to order it from another library through inter - library loan systems. So, it's definitely worth giving your local library a try.