Faculty often tell students to use scholarly (or academic) sources rather than popular ones. This distinction applies most often to the use of articles found in journals, periodicals, and magazines. Many of the same distinctions apply to books. The author’s credentials, the writing style, the presence (or lack) of footnotes, and the type of publisher (university press or mass-market publishing house) should all be looked at when evaluating the quality of a particular book. 

Understanding the Peer Review Process

What is peer review? How do articles get peer reviewd? Why is peer reveiw important? 
Watch this short video from NC State University Libraries on the peer review process:
Peer Review in Three Minutes