Lengthy books may require part dividers to group similar chapters within the document. Because readers often merely glance at the part divider page, keep the text on the divider page minimal and succinct.
Never include any information on the divider that is essential to the topic discussed in the chapters. For example, instructions to turn off the power before proceeding with the tasks in the chapters are not appropriate on the divider. However, an explanation of why the chapters are grouped into a part could be helpful to a reader.
Typically, when you prepare part dividers for computer documentation:
Organizations vary in their choice of using either Arabic or Roman numerals for the part number.
For example, you could use graphics on the front of the part divider with text on the back, or a combination of text and graphics on the front with text continuing on the back.