An overview or rough summary — a concise explanation of a subject, often used as an introduction before detailed discussion.
講義の冒頭で研究分野の概説が行われた。
At the start of the lecture, an overview of the research field was given.
教科書の第1章は統計学の概説になっている。
Chapter 1 of the textbook is an introduction to statistics.
論文の冒頭で背景と概説を簡潔に述べた。
I briefly stated the background and an overview at the beginning of the paper.