During the period of World War 1, the First Sergeants often carried a book in their pockets that contained administrative files. This book, which today may be known as a "leaders book" contained the names of everyone in the company and their professional history (AWOLs, Work Habits, Promotions, etc.). This book was passed from First Sergeant to First Sergeant, staying within the company and providing the unit historical information. What was this book called?
A Black Book.