By William Cane
Your book proposal should contain one or two sample chapters. Since the structure and length of sample chapters is entirely up to you, no more will be said here about the content of those chapters. You should not include the Introduction or Chapter 1, however, as these are usually considered too introductory. Better to include one or two chapters from the middle of the book. Including the final chapter is also not recommended, especially if it has a conclusory tone.
This photo of Martha Gellhorn shows her reviewing some sample chapters for her book Face of War. One of the most gifted war correspondents of her time, she covered World War Two extensively. She was also Hemingway's third wife. Like Hemingway, she enjoyed adventure and travel.
If you write about what you enjoy, as Gellhorn did, your sample chapters will have the kind of vim and vigor that will convince editors to buy your book. Don't be afraid to take risks with your writing, especially with your sample chapters. If you go overboard, editors will let you know soon enough. But if you play it too safe and turn in drab copy, they might just be bored.