Here are a some words that sometimes get confused by folks in the hobby publishing industry. Using the correct term will contribute a professional appearance to your work. These aren't my words but I am unable to provide a cite, apparently I accidentally deleted it from the text at some point.
A foreword, if we follow the generally accepted
definition in publishing, is an introduction to a book by someone
other than the author. It comes right after the Table of Contents,
and the pages are numbered with lower-case Roman numerals, e.g., i,
ii, iii, etc., rather than the Arabic numerals used for the text of
the book.
Ideally, it's written by an expert on the subject of the book who
says that the author did a good job writing about the subject. The
foreword generally speaks well of the author.
A foreword, as the spelling indicates, is a word that
comes before. It's not a forward, which is a
direction, or a foreward, which is a misspelling.
A preface is usually written by the author of a
book and often gives an overview of how the book came to be written,
its intended purpose, and to what extent it covers the topic. It may
come before or after the foreword, but it usually comes after and
follows the same page numbering system. The preface may also include
acknowledgements.
An introduction is also written by the author (or,
sometimes, the editor). It's an essay that sets up the full topic of
a book. It states what the author's point of view is and may indicate
what the reader's point of view should be. After reading the
introduction to find out what's in the book, the reader can decide
whether or not to read it. Since it's part of the text, the pages are
numbered with the same numbering system as the text.