""A Defense of the Original Principles of the Society of Friends: In a Series of Letters"" is a book written by Henry Martin and originally published in 1836. The book is a defense of the Quaker faith, also known as the Society of Friends, which was founded in the 17th century. The author argues that the original principles of the Quaker faith, such as the importance of individual conscience, the rejection of formal religious hierarchies, and the...