The book "A Brief Description of the Birth and Development of the People Called Quakers" by the famous English writer and philosopher William Penn is an important work devoted to the history and philosophy of the Quaker religious movement. The author tries to give the reader an understanding of the origin and development of this religious group, revealing the key events and ideas that formed the basis of the Quaker movement. In his book, Penn describes the principles and practices of Quakers, emphasizing their beliefs in inner Light and peacefulness. This work helps to better understand the essence of the Quaker movement and its contribution to religious and social history.