At 230-odd pages, a much shorter novel than The Bone Clocks or Cloud Atlas, Slade House is set within the same universe as The Bone Clocks, but is not a sequel. It's more of a companion piece. You wouldn't have to read both, but I would recommend that you do.
The novel begins in 1979, and proceeds in nine year intervals, ending at Hallowe'en 2015. It's a 'haunted house' novel, but the house only appears every nine years, and each time it appears, someone is summoned there, and each time, meets a disturbing fate. There is necessarily some repetition here, but just when you think you know what's going to happen, the ground shifts..
This is an unnerving novel, very dark, very intricately woven, very clever. It's a small but perfectly formed horror story, exceedingly well written. I'm looking forward to his next book!