I've read it about 7 times in 20 years, it inspired me to read other Lincoln biographies. I would say it's closer to a biography than a novel, from what I could tell from historical accounts, he doesn't make up too much. It's a not altogether flattering portrait of Lincoln (but which of Vidal's books is?). If you like reading the foibles of the beautiful people of the time, which is what Vidal seemingly is obsessed with, you will like this one.