Journal articles are shorter pieces of writing than a book: for example, they are often ten to twenty pages long. They are usually based in academic research and written by an academic, often a faculty member or a graduate student. And, they are published through the process of peer review. Peer review is the process by which the author's peers - that is, other experts in the field - read the article before it's published. So, they read it, they comment on it, they assess it in terms of its value, its contribution to the field, all sorts of criteria, and if it's found to be a good solid piece of work, at that point the journal article might be published. So, that review process is what separates the academic information from the more popular information that we are able to find either in a public library or on the free web, because in most cases the items purchased there or available there have not undergone that process of peer review.