The purpose of a foreword in a book is to introduce the author or topic and encourage the reader to finish the book. A foreword is not written by the author of the book.
A foreword is typically written by someone who has special knowledge about the author or subject of the book and is, therefore, able to explain why the book should be read. This part of the book differs from the preface, which is written by the author. This section includes information about why and how the author became involved in the subject. In a book's introduction, the author paves the way for the reader, providing background information or an overview about the topic.