When you're working on any type of longer document ‚ a saddle -stitched booklet, a magazine, a perfect-bound textbook ‚ you can easily spend more time on tracking project files, communicating with your workgroup, and manually creating tables of contents and indexes than you spend designing the publication. Longer projects such as these generally consist of multiple InDesign documents, which lets multiple users work on the project and creates smaller, more manageable documents. If you're working on this type of document, by yourself or in a workgroup, InDesign provides the Book feature for managing the document files, updating page numbers across documents, and ensuring consistency in the book.
For longer projects, InDesign also provides its Table of Contents feature, which lets you create and update automatically formatted tables of contents (TOCs). These TOCs are compiled from text formatted with specific paragraph style sheets (heads, subheads, and so on). If your publication needs an index, you can tag words throughout your text, then generate an automatically formatted index using the Index feature. The Table of Contents and Index features both work in single documents and for an entire book (and they both transfer to documents exported in PDF form).