I am currently reading my way through a long list of science fiction and fantasy titles. (http://www.npr.org/2011/08/07/138938145/science-fiction-and-fantasy-finalists if you are interested in the list).
There are only 4 stories about Callahan's Place in this little volume. Robinson has filled in with other writings (including what ended up being Chapter 2 of his novel Mindkiller, which I read earlier this year).
There is one interesting little essay on how he felt about being a book reviewer for a sci-fi magazine. How do you review books by your friends?
Light easy reading!