what is the Jekyll's significance in the novel?

Jekyll is the "good" part of his being who wants to experience wild abandon without regret. He wants to break through the Victorian shackles of social etiquette and repressed desire. The doctor's belief that within each human being there exist forces of good and evil leads to his experiments that try to separate the two. Although presented as a scientific experiment, Jekyll undertook this task to allow himself a release from the respectable guise of Dr. Jekyll. In the book, Jekyll's voice is only heard in the concluding chapter, only after being described through the lens of Utterson, Lanyon, Poole, and Enfield.