In this rather lengthy chapter, the narrator describes the profound influence the yellow book has on Dorian – it totally changes his life.
The book involves a young Parisian hero, who reminds Dorian a lot of himself. The hero, like Dorian, was once incredibly beautiful, but suddenly loses his beauty. This terrifies Dorian.
As the years pass, Dorian remains as beautiful as ever. Even though awful rumors circulate about him, people still love Dorian because of his seemingly innocent, golden beauty.
Dorian often looks at the portrait, and takes pleasure in the aging, corrupt image on the canvas. He's morbidly obsessed with it, and delights in comparing his own untouched beauty with the marred portrait.
It turns out that Dorian is still hanging out with Lord Henry, who's helped him become a leader of the decadent social scene. All the young men try to imitate his grace and elegance.
Dorian, however, wants to be more than just a figure of fashion. He strives to understand, well, basically everything about human nature. He longs to find new sensations and pleasures everywhere.
In his explorations, Dorian dabbles in the ritualized beauties of Catholicism, then decides (surprise, surprise!) that the Church is not for him.
Dorian also dabbles at a lot of other things, like perfumery, music, jewels, famous luxury goods of antiquity, and textiles. We get a long, long list of his various acquisitions and obsessions. He's really, really into collecting stuff.
All of Dorian's accumulated goods are just distractions from his real fascination – the portrait. After a while, he can't bear to be away from it for too long, and he becomes stranger and stranger.
Society takes note of Dorian's increasing oddness, and not in a good way. Mysterious rumors about him catch on like wildfire.
The scandals only serve to make Dorian more seductive and fascinating, however, and he goes about his business relatively undisturbed.
In his personal time, Dorian loves to stroll through the picture gallery of his country house, looking at the portraits of his famous (or infamous) ancestors. He also ponders his literary and historical "ancestors," such as the hero of the yellow book.
Disturbingly, we see that Dorian is obsessed with decadent violence. He's fascinated by sinners of the past, and he finds aesthetic pleasure in grotesque crimes of antiquity.
The narrator blames the yellow book for Dorian's state of mind, saying that it taught him to see evil as beautiful.