This introduction presents an overview of key concepts covered in the subsequent chapters of this book. The book analyzes the writings of a minister of the Unitarian Church that is an intellectual journalist who wrote on social, political, economic, philosophical and theological issues, two historians: George Bancroft and Francis Parkman, and a professional politician, Abraham Lincoln. In the more secularized America of the early nineteenth century, the special mission had become the fostering of the spirit of liberty. Abraham Lincoln's faith was the noblest American faith of the age: faith in the right of all men to develop their humanity to the full. To the modern reader the most striking characteristic of William Ellery Channing's lecture is likely to be its sheer daring, its bold readiness to generalize over a range of topics each of which nowadays constitutes a distinct intellectual discipline with its own specialized vocabulary and its own methodology.