Strange Case of Dr Jekyll and Mr Hyde

In early March, Jekyll's butler, Mr. Poole, visits Utterson and says Jekyll has secluded himself in his laboratory for weeks. Utterson and Poole break into the laboratory, where they find Hyde wearing Jekyll's clothes and apparently dead from suicide. They find a letter from Jekyll to Utterson. Utterson reads Lanyon's letter, then Jekyll's. Lanyon's letter reveals his deterioration resulted from the shock of seeing Hyde drink a serum that turned him into Jekyll. Jekyll's letter explains that he had indulged in unstated vices and feared discovery. He found a way to transform himself and thereby indulge his vices without fear of detection. Jekyll's transformed personality, Hyde, was evil, self-indulgent, and uncaring to anyone but himself. Initially, Jekyll controlled the transformations with the serum, but one night in August, he became Hyde involuntarily in his sleep.

Question: was dr. jekyll and mr. hyde the same person
Answer: yes