I used the concept of peer review heavily when I wrote my award-winning science textbooks. Even though I have a PhD in nuclear chemistry, I don’t know everything there is to know about chemistry. Thus, in order to ensure that my chemistry text was accurate, I had other PhD chemists (and one high school teacher) review the book to catch errors so that I could correct them. As I started writing textbooks that were further and further from my field of expertise, I had to rely on peer review more heavily.
While the concept of peer review is an excellent one, the execution of it in modern science has been questioned in many different ways. Some scientists think that peer review tends to enforce orthodoxy, making it very difficult for new and revolutionary ideas to be published. Others see peer review as a way for the reviewers to keep people they don’t like from getting published. Others say that is a way for reviewers to punish their rivals.
Over the years, several studies have tried to address the validity of the peer-review process, and unfortunately, the results have not been very good.