Just finished up The Kubikiri Cycle by Nisio Isin. Full title translates "The Beheading Cycle: The Blue Savant and the Nonsense Bearer." It was fascinating as expected from him.
What a strange murder mystery. A bored heiress invites some eccentric geniuses to a deserted island to hang out, but soon people start getting beheaded. The main character, a tagalong and non-genius who sleeps in the storage room, tries to solve the case, but almost no one is cooperative.

As it turns out, this is his first published novel! He also wrote the -monogatari series which is being adapted into a fairly popular anime. Even though it's part of a series, it stands completely on its own. I don't want to spoil much of anything, but Isin has a lot of respect for his readers. As a fan of mysteries, absurdism, and Nisio Isin's work, I really enjoyed it.
Now that Del Rey Manga has been bought out, I don't know if anyone will keep translating this series. I understand why - it's pretty unapproachable. Shame.