One way you can identify a book is that the citation gives a publisher and a year of publication, but usually not a month and volume, as a journal article would. A journal is a scholarly periodical, and usually the articles are peer reviewed, meaning other scientists evaluate each article before it is published. Primary literature reports original research for the first time, i.e., a scientist does an experiment in the lab, then writes an article or book or dissertation, or appears at a conference to tell other scientists the results of the experiment. It is important in the scientific community that peer reviewers and other scientists can repeat the experiments, both prior to and after publication, and that the source document is readily available for this purpose. Bibliographies or citations at the end may lead you to other useful monographs and articles on the topic.
Secondary literature is derived from primary literature.
It synthesizes, summarizes, and provides access to primary literature. An example of secondary literature is your textbook for this class. Bibliographies or citations at the end may lead you to other useful monographs or articles. An index is a list that helps you to find information about a particular topic. It may be in the back of a book, listing the information you can find in that book, or it may be a print or electronic periodical index, a book or database to help you find specific articles related to a particular topic.