The Dangers of Beauty
Zuleika Dobson is an extraordinarily attractive woman, and her beauty causes all men she meets to instantly fall in love with her. Beauty is a wonderful part of life, and it brings great pleasure, but it can also hold great danger; an ugly witch is to be expected, but a beautiful sorceress is another kind of terrible thing altogether. There is peril in beauty, and this novel demonstrates this theme on a large, dramatic scale, as the Oxford undergraduates' infatuation with Zuleika leads them all to commit suicide. Beauty enjoyed in its proper place is good, but when it receives disproportionate affection at the expense of other virtues, it can lead to great danger and foolishness.
The Weakness of Man
The susceptibility of man to the appearance of beauty is on full display in this novel, even satirized. This theme is hilariously evident in the way every man who sees Zuleika instantly falls in love with her, even if glimpsed only for a second. Man's weakness is also ridiculed as all of the Oxford undergraduates simultaneously commit suicide as a sign of their love and devotion for Zuleika, an outcome that is obviously unlikely, but one that highlights the foolishness of young men in the realm of new, unfamiliar passions. The ironic humor of this mass act is particularly evident in the way the staff of Oxford doesn't even really notice the absence of all their students, ensuring that the reader sees this as humorous satire rather than serious commentary.
Social Isolation
Both of the novel's main characters, Zuleika and the Duke of Dorset, are admired by their compatriots, yet live in a state of social isolation. The Duke's isolation is more literal; being an unusually talented young man with a bit of snobbishness, he doesn't really associate with other students, whom he finds jarring and distasteful, leaving him in a state of contented loneliness. Zuleika, on the other hand, is always interacting with those who find her attractive, and she never wants for company; as a result of her appearance, however, she never finds anyone who loves her simply for herself, not being blinded by her beauty. She, therefore, lives in isolation, longing for someone with whom to enjoy a real friendship - even love.