Third book in Stross’s series about Miriam Beckstein, a woman who discovers that she is part of a family who can step between different alternate versions of the Earth. This volume is thick with intrigue, some of it nearly incomprehensible in its complexity. And yet despite all the plotting and scheming and maneuvering, there is essentially no change in the characters’ conditions in the entire course of the book until its closing pages. It’s a middle book that I think could have been reduced to a couple of chapters with no loss. Disappointing.