This omnibus consists of the short story “The Borders of Infinity”, and the books Brothers in Arms (which I’d previously read) and Mirror Dance. All the stories deal with Miles Vorkosigan’s alter ego Admiral Miles Naismith, commander of the Dendarii mercenaries. More importantly, the two books deal with his clone brother, Mark.
In Brothers in Arms, Miles deals with having a clone with a great deal of equanimity, welcoming him as a brother – which makes sense when you remember his mother is a Betan, and has very liberal views about such things. At the end of that book, Mark escapes, but Miles wants to find him, and convince him that he really does consider him family.
Mirror Dance is Mark’s story of how that happens, mostly because Miles is dead for most of the book. (Which makes sense with the level of technology in this universe.) Mark has a pretty complicated (one might even say horrific) journey to even accept that he might want to be Lord Mark Vorkosigan. It’s an amazing story – absolutely typical of why I love these books. Bujold really makes you think about a lot of things in the course of these stories.