Unlocked, by John Scalzi

In Lock In, John Scalzi sets a murder mystery in a near-future world where many people suffer from Haden's, a disease that paralyzes the victim, giving them "lock in," a state of full mental awareness but with no ability to move.  Through the course of the story, the reader can infer much about the disease and its implications, but for a fuller picture, Scalzi has written a prequel of sorts, Unlocked: An Oral History of Haden's Syndrome.

In terms of story telling, Unlocked doesn't deliver in the same way that Lock-In does; the subtitle tells you that much.  Nevertheless, Scalzi convincingly relates the history of the disease through the voices of doctors, journalists, and others affected by the disease.  Had I not read Lock In, I am certain I would not have enjoyed Unlocked as much, but Unlocked is essential for fans of Lock In.