Like the other books in the Wild Cards series, this book is an anthology work, but also an ongoing story as a whole, with various writers writing their own part of this superhero/alien invasion/ secret society story. Most of the stories as independent pieces are pretty good, but taken together, the shifts in tone and focus make the threat seem less important, and the characters a little schizophrenic. If, however, you're looking for some superhero prose fiction, you could do a lot worse.