"This Mortal Coil" is a science fiction novel by Gideon the Ninth author Tamsyn Muir. It explores themes of identity, mortality, and the nature of consciousness through a unique blend of fantasy and technology. The story is set in a world where people can upload their consciousness into a digital realm, allowing them to live beyond their physical bodies. The narrative follows Coiled and her journey as she navigates a society grappling with the implications of immortality and the ethical dilemmas that arise from it. The book delves into the complexities of human experience, questioning what it truly means to be alive.