It is the purpose of this book to trace the course of this tradition in the English drama, to appraise the inheritance of each age from the preceding ages, its borrowings from other national inheritances, and the profit and loss due to its own invention or industry. All that may be attempted here by way of preliminary definition is a glance at the main European course of the classical tradition to see what have been from time to time considered the essentials of tragedy and to ask how far there has been any agreement in regard to these essentials. The basis for much of modern theorizing has been Aristotle's tentative yet searching analysis of Athenian tragedy. Many of the peculiarities of Athenian tragedy--its structure without acts but with a chorus, its limitation of three actors on the stage at once, its narrow range of mythological subjects--are evidently not essential to securing tragic effect. Even the unities, whether as observed in the Greek theatre or as defined by French and Italian critics, may, after generations of debate, be safely relegated as nonessential. Omitting, then, what no one would now insist upon as requisite, we may derive from the "Poetics" something like the following:-- Tragedy is a form of drama exciting the emotions of pity and fear. Its action should be single and complete, presenting a reversal of fortune, involving persons renowned and of superior attainments, and it should be written in poetry embellished with every kind of artistic expression. Much more than this has been derived from Aristotle by modern theorists, but this much of the classical conception has generally survived in modern tragedy. If the meaning of "a single and complete action" be stretched a little, this definition includes the plays of Shakespeare as well as those of Racine, and nearly all tragedies from the Renaissance to the present.