The Fault in Our Stars by John Green

Hazel Grace Lancaster is pretty charmed by Augustus Waters. That is, until he pulls out a cigarette. After meeting at a support group for teens with cancer, nothing could be less of a turn on than actively giving yourself cancer. Luckily for Augustus, he's never actually lit one. Hazel is surviving with cancer, because of the use of a new experimental drug. Gus conquered his cancer by sacrificing his leg. They're instantly drawn to one another, but what is the point of romance when cancer turns you into a grenade? Hazel can't let herself fall in love for fear of causing more heartache than joy in her short lifetime. But Augustus Waters thinks it's worth it, even if it's just for their short infinity of days.