The Strange Case of Dr. Jekyll & Mr. Hyde & Other Stories (Signature Editions) by Robert Louis Stevenson

What a study in contrasts is the friendship between Henry Jekyll and his boon companion, Edward Hyde. Where Jekyll is a handsome and respected man of science, Hyde is a surly and brutish misanthrope. Nevertheless, Jekyll has allowed Hyde free access to his home and laboratory and, surprisingly, made him the sole beneficiary of his will. Given the closeness of their bond, it seems peculiar that no one has ever seen the two men together in public. And yet they share a remarkable chemistry . . .

First published in 1886, The Strange Case of Dr. Jekyll and Mr. Hyde is Robert Louis Stevenson's classic tale of the duality of human nature and his iconic presentation of what would come to be referred to as the "split personality."