The editor came across the unpublished texts included in this volume as early as 1905. Perhaps he ought to apologize for delaying their appearance in print. The fact is he has long been afraid of overrating their intrinsic value. But as the great Shelley centenary year has come, perhaps this little monument of his wife's collaboration may take its modest place among the tributes which will be paid to his memory. For Mary Shelley's mythological dramas can at least claim to be the proper setting for some of the most beautiful lyrics of the poet, which so far have been read in undue isolation. And even as a literary sign of those times, as an example of that classical renaissance which the romantic period fostered, they may not be altogether negligible. These biographical and literary points have been dealt with in an introduction for which the kindest help was long ago received from the late Dr. Garnett and the late Lord Abinger.