If you are a fan of the manga then you will most likely enjoy this season. For those who are familiar with the manga series Black Butler Book of Circus is the fourth arc of the manga storyline. This storyline is a continuation of the first season (up to the Indian Butler arc around episode 15 in the anime) and remains true to the dark and graphic(at times) nature of the series. For those who were disappointed with Black Butler II (the second season that was not related to the manga, but it's own season) than this will definitely be something worthwhile. Because there are only 10 episodes it is a fast series (though still longer than the Book of Murder which was broken down into two movies in Japan). It would have been nice if they had included book of murder to this as well since that series was short but I'm just excited that they actually dubbed and released both of these seasons in the U.S. given the length of time between each of the seasons.