Refers to the introductory section of a book, thesis, or formal argument. More formal than はじめに.
State the purpose of the research in the introduction of the thesis.
Reading the preface of this book will give you an overview of its structure.
序論 is the structured introduction section of an academic paper or essay, while 前置き is casual preliminary talk before getting to the point.
Composed of 序 (order, preface) and 論 (argument, discourse). The kanji combination directly conveys the meaning of an introductory discussion.