This is a collection of shorts set in the universe Hamilton has created for the Reality Dysfunction series. I think these are short stories he worked on while he was playing with the idea for the universe the Dysfunction books are set in.
You don't have to read this first to understand the Dysfunction stuff. I think this is one of those must have books for people (like me) who didn't get enough of the series. I recommend this and any thing else by this author.