John Scalzi’s Lock In introduces the reader to a world in the near future where millions of people have been affected by a virus that immobilizes the body but leaves the brain fully functional, while others have had their brains altered but still have fully functional bodies. Those who are immobilized are “locked in” and can use “threeps,” or robotic bodies, to interact with others in the physical world; those who have had their brain chemistry changed but have had no other physical effects are called Integrators and can allow those who have been “locked in” to borrow their bodies for a time. Hadens, those who have lost the ability to use their bodies due to this virus, find themselves in a new community that can exist outside of the physical realm, because they are not attached to their bodies. Scalzi does some interesting world-building and purposefully leaves the protagonist, Chris Shane, ambiguous. For example, Chris’s gender and race are hardly mentioned, which leaves the reader to interpret how Chris interacts with the world as an FBI agent looking to solve a murder that may have involved Hadens. I appreciated Scalzi’s subtle inclusion of diversity in the novel, and I look forward to reading more from him.