“The Bluebook: A Uniform System of Citation, Twenty First Edition” is a textbook published by the Harvard Law Review Association in 2021. It is a spiral-bound format book authored by the Columbia Law Review, focused on the subject areas of law and education. The book is written in English and Middle English and is an essential reference for legal professionals and students alike. With its detailed citation guidelines and authoritative content, this textbook is a valuable resource for anyone working in the field of law.