Here's the classic 1936 translation of Beaudelaire's masterpiece, presented in a bilingual, parallel text softcover edition for the first time in... well, awhile; also includes Millay's original 32 page preface.

Here's NYRB:

Charles Baudelaire invented modern poetry, and Flowers of Evil has been a bible for poets from Arthur Rimbaud to T. S. Eliot to Edna St. Vincent Millay, who, with George Dillon, composed an inspired rhymed version of the book published in 1936 and reprinted here, with the French originals, for the first time in many years.

Millay and Dillon, while respectful of the spirit of the originals, lay claim to them as to a rightful inheritance, setting Baudelaire’s flowing lines to the music of English. The result is one of the most persuasive renditions of the French poet’s opulence, his tortured consciousness, and his troubling sensuality, as well as an impressive reimagining of his rhymes and rhythms on a par with Marianne Moore’s La Fontaine or Richard Wilbur’s Molière.

 

In [Millay and Dillon’s] Flowers of Evil a path has been opened for the blending of French and English poetry. Here are translations not smelling at all of the dictionary. ‘The Litanies of Satan’ in particular seems to come from a dim chapel draped with black banners.... Let us hope that this book will stand as an English Baudelaire for some time, without the guidebook counterparts.
—Agnes Lee Freer, Poetry