A book is a work that is published once, not as part of a regular series. More specifically, an edited book is one that is divided into chapters, each of which is written by a different author or group of authors. If the work you are using is not divided up in this way, go to the page, Books .
Edited books are valuable in that the individual chapters are generally authored by specialists.
Sometimes the chapters were originally published as journal articles, and are reprinted because of their enduring importance. In other cases, the editors have asked authors with differing perspectives to state their points of view on a single topic. Be careful, though. Like the other type of book, edited books can become outdated. It is therefore important to make sure the edited books you use in your research are current and valid.