A preface is a piece of text that introduces the author and the book to the reader. It is generally written by someone who is not the book's author or editor. Forewords can also act as a form of book endorsement. The person speaking on behalf of the book may or may not be related to the publisher.
A prefatory word, phrase, or clause is one that explains or clarifies some aspect of the work itself or of its production. For example, a writer might include a prefatory note explaining some aspect of the history of the manuscript or document being described. Many books contain a prefatory material section in which the author(s) discuss their intentions in writing the work, often including a brief description of the contents.
A prolegomenon is a term used in philosophy and theology for any discussion that does not proceed from where it is assumed that the reader will start. Thus, a prolegomenon to analytic philosophy would be any discussion of concepts relevant to analysis but not themselves analyzed. In theology, a prolegomenon is any discussion of topics raised by the biblical texts without assuming familiarity with those texts.
Prologue A prologue is a short introductory passage included at the beginning of a book or other lengthy publication. They are often written by famous people involved with the project to introduce it to the public.
Someone other than the author writes the preface, which tells readers why they should read the book. The author writes a preface that explains readers how and why the book came to be. These elements are not the same.
The foreword is the introductory chapter of the book. It usually comes before the main body of the text, but it can also follow it. In either case, it is written by someone else -- often but not always the author of the book -- who offers his or her opinion about the work. This person may also suggest other books that readers may find interesting or useful.
Often, but not always, the foreword and preface are included in early editions of the book. More recently published books tend not to include an introduction or conclusion. Instead, editors like to keep pages free for content, so the best way to provide context for your readers is with subheads and topic sentences within the body of the essay.
An introduction introduces readers to the manuscript's primary subjects and prepares them for what they might anticipate. A foreword is used to introduce another work by the same author or someone else with which the original writer or artist was associated.
The foreword should be written by someone who knows the author or artist well. It can be anyone from the author's or artist's family to a close friend. The foreword writer should choose someone who can speak from experience about the life of the author or artist. For example, if the author or artist was a political leader, a biographer might want to write a foreword on their life. If the author or artist created a character, a critic could discuss similarities between their own life and the character's story.
The foreword should start off by telling readers something about the author or artist. For example, it may describe their personal history, their creative process, or any other information relevant to understanding why they wrote or created what is being introduced. The foreword writer should also mention any books that are coming out around the same time as the main work, since people may not know about these other projects.
Finally, the foreword should end with a call to action.
Here's an example of a foreword: