Piketty's book was not peer-reviewed, but as it's often the case in all fields you first publish a bunch of peer-reviewed articles on a subject and then you sum

Piketty's book was not peer-reviewed, but as it's often the case in all fields you first publish a bunch of peer-reviewed articles on a subject and then you summarize and clarify stuff putting together a book. So the book itself might not be peer-reviewed, but many of the findings within are