Glitches (Lunar Chronicles, #0.5)
A great little Novella (short story? Is it long enough to be called a novella?) written as a prequel to Cinder. I enjoyed learning about Cinder's first few weeks living with her step-family, and how the relationships we know from Cinder began to form. I don't think anything at all was revealed that wasn't already referred to or suggested in the novel, but it was still a nice little addition to the ongoing story.