By prescription, which often has the force of law, a book should have both a Preface and an Introduction: the first relating to the writer; the second to the things written. I may well dispense with the latter, for what is here written the humblest capacity can understand; and it would be cruel to detain him long on the porch who is anxious to enter the building. But, dear reader, a word with you (for that is the meaning of "Preface") before you begin this unpretentious little book, the joint production of an author, an editor, and a publisher. It is due the first, to say.
