preface
n. countable B2 Upper Intermediate US //ˈpɹɛfəs// UK //pɹˈɛfəs// pref·ace
n. an introduction at the start of a book or speech. It usually explains why the author wrote the book and what it is about.
n. an introductory passage in a book or other literary work, typically written by the author to explain the scope, intention, or background of the text.
The author explains her research methods in the preface.
I usually skip the preface and go straight to the first chapter, but this one was actually quite helpful.
In the preface to the second edition, the philosopher addresses several criticisms that had been leveled against his original thesis since its publication.
Usage
Often takes the preposition 'to' when identifying the work it introduces.