Each selection has been thoroughly reedited, and the order of the poems has been rearranged in light of redating or other reconsiderations. All headnotes are new or updated, and many footnotes have been added, replaced, or revised.

Criticism reflects the recent renaissance in Shelley studies, the greatest renaissance since 1870-92. All twenty-three essays are new to the Second Edition; among them are the work of Harold Bloom, Stuart Curran, Annette Wheeler Cafarelli, Michael Ferber, James Chandler, and Susan J. Wolfson.

A Chronology, an updated Selected Bibliography, and an Index of Titles and First Lines are included.