Using the index
If the chapter headings are not clear enough for you to determine the book's usefulness, read the index. Not every book has an index, but when one does, it is an invaluable tool. The index lists in alphabetical order the pages on which different persons or subjects are discussed. The index in a book on the Progressive Party in Wisconsin will list each of the pages on which Robert M. LaFollette is mentioned. It may even break this down and tell you which pages discuss LaFollette's early career, which discuss his campaigns for the presidency, and so on. When the scope of a book is very broad, the index is the best guide to finding that portion of it that is closest to your topic. Remember, however, that unless you read more of the book than just those pages that deal with your topic, you will not know the author's biases or conclusions, and these may be of great importance. Although you may want to select only small portions of a book to use in your research, if any of your own conclusions are drawn from a particular work, you will need to know its overall contents.
The introduction, conclusion, and bibliography
If the book has no index, or if you wish to get the flavor of the work as a whole before selecting it as a source for your paper, the introduction, conclusion, and bibliography may be of help. Authors often explain some of their purposes and conclusions in the introduction, and a look at the bibliography (if one is included) will give clues as to what sources the author felt were important and how extensive his or her own research was.