Include copies of previous work with the final proposal, and any glowing or controversial reviews etc. In this section you must describe what you see as the market for your book. Describe your typical reader in as much detail as possible including age, gender, social groups, lifestyle and reading habits. If there is a definable group who will buy it, you must name the group and indicate how big it is. Also mention other books of a similar nature which might sit on the shelf next to yours, and you should mention how successful they have been so that the publisher can predict how yours might fare.
Publishers can offset a considerable portion of their expenses with a good serial sale.
This is, of course, the heart of your proposal. It must demonstrate that you're capable of realizing the full potential of the book's concept and that you can organize information clearly and logically so that it is accessible to the reader. A brief but irresistible introduction to explain and summarize the chapter. Every heading and subheading within each chapter. These will provide ample detail, and ensure that all elements of the idea are given adequate and appropriate coverage.