Stephen Moss I don't think this has adult themes, per se, though some scenes have some fairly graphic violence and adult language. As others have said, I would think its is nothing that a teenager would balk at. Hope you enjoy it.
Catherine I always thought a book labelled as "Young Adult" was more that the characters, writing style & content was aimed at a teenager, rather than the amount of swearing or sex it contained.
Bob Johnson I don't see anything in this book that would not be appropriate for a young adult. Anyone who enjoys science fiction and are over the age of 14/15 will enjoy it. There are some grammatical and editing errors, it's still a fun read.