Dr. Jekyll and Mr. Hyde by Robert Louis Stevenson
Here's the aforementioned Part 2 of the DJ&MH illustrations. Dr. Jekyll is all sophistication on the surface, and to his friends. On the inside, however, he has been leading a double life. While he is mostly an upstanding citizen, a part craves to be immoral and indulge in guilt, shady pleasure, and debauchery.
It is mentioned in the story that Jekyll had been leading a secret life to explore some of this hidden displeasure. So when he started stumbling upon some chemical concoction that was able to bring out the duality of man, to separate it physically for some time, he became excited.
At first he reveled in the notion of becoming Edward Hyde, a figure of anti-morals. As he started losing control of Hyde, and sensing the wildness and hatred swell, he became fearful and panicked. Who wouldn't, really?
About the illustration:
For some reason I drew Jekyll as being rather young, even though he isn't really. I guess it was his giddiness to experiment with the potion that made me skew towards a more energetic, youthful appearance. Or maybe I wasn't thinking when I drew it...
This booksketch was done with inkwash, a little Micron pen and made to be a duotone in Photoshop.