the.com/preface

means a short introductory section at the start of a book, where the author explains how or why it came to be written.

from From Latin praefatio, 'a saying beforehand,' built from prae- 'before' and fari 'to speak' — literally the words spoken in front. The fari root is the same one that gives us 'fable,' 'fate,' and 'infant' (literally 'one who cannot yet speak'), all clustered around the simple, ancient act of speaking. It reached English through Old French in the late Middle Ages.