A book that I recently and quite by accident came across – Greg Egan’s Schild’s Ladder – comes pretty close to being an excellent sci-fi book of the proper kind. Set some 20 thousand years in the future, it focuses around the problem of dealing with a viciously expanding new kind of a vacuum, accidentally created by an experiment, that is destroying our universe with its laws and principles in its path. Even though this is the central axis of the book, many interesting details are revolving around it. Space travel through your identity being transmitted as a signal from one point to the other; human and non-human bodies, which this identity can inhabit and swap; completely bodyless existence; slowing down and speeding up of perceived time to alter the experience of events; and so on. It really is a treat to the mind, regardless of some of its weaker sides and despite the fact that at some points it goes onto territory which is quite incomprehensible and unimaginable.