Glasshouse is now my favourite Charles Stross book. It’s about a person with a bunch of memory gaps who volunteers to join an experimental colony where the people are recreating the Dark Ages of the mid-late twentieth century on Earth. And as things go on, gaps in his memory fill in and things get awesome. It deals with the issues of the past and identity and how people are their memories.
There’s a chunk where I was actually “Oh shit, how is she going to get out of this?” which I don’t get from his more space operatic Singularity Sky and Iron Sunrise where everyone seems so competent and brilliant Neal Stephenson should be writing them. A big part of Glasshouse’s appeal is that the main character, Robin, spends most of the book stuck in the body of a waifish orthodox human female (orthodox meaning piddly upper body strength, fertile, only two arms), when his past includes being a swordmaster, a tank and other big brutal direct things. There’s a lot of good stuff in there. If you like that sort of thing.