Most of the chapters which make up the present volume have already
appeared, in earlier versions, in certain magazines; and to the editors of
_The Forum_, _The North American Review_, _The Smart Set_, and _The
Bookman_, I am indebted for permission to republish such materials as I
have culled from my contributions to their pages. Though these papers were
written at different times and for different immediate circles of
subscribers, they were all designed from the outset to illustrate certain
steady central principles of dramatic criticism; and, thus collected, they
afford, I think, a consistent exposition of the most important points in
the theory of the theatre. The introductory chapter, entitled _What is a
Play?_, has not, in any form, appeared in print before; and all the other
papers have been diligently revised, and in many passages entirely
rewritten.