The foreword of a self-written book should first briefly introduce the theme and background of the book so that the readers can understand the main content and significance of the book. Next, you can express your determination and reason for writing this book, and explain your understanding and expectations for this book. It could explain the purpose and meaning of writing this book and express gratitude and expectations to the readers. Finally, you can briefly review the main plot and characters of the book, emphasize the theme and values of the book, and provide some recommendations and reader feedback so that readers can better understand the value and significance of the book. In short, the foreword of a self-written book should be concise and clear to express the author's expectations and determination for the book. At the same time, it should also let the readers understand the main content and significance of the book.