If you're looking for a little more information first, here you go:
Hazel Grace Lancaster, age 16, was diagnosed with cancer three years ago. She has never been anything but terminal, but thanks to a wonder drug, she is currently stable. In an effort to cure her "depression," her well-meaning parents force her to go to a Support Group, which is pretty awful, aside from the fact that she eventually meets 17-year-old Augustus Waters there. Augustus had a bout with cancer himself a few years back and lost one of his legs, but he's in remission and only attends the Support Group as a favor to he and Hazel's mutual friend Isaac, who is about to have his cancerous eyes removed, resulting in blindness.
Let me pause right there. Yes, this is a book about kids with cancer. But it is not a "cancer book." It's an amazing story about contemplating what really matters in this life. Yes, it is sad. I will admit that every time I read more than a single paragraph, I bawled like a baby (particularly in the second half of the book--but I blame that largely on the pregnancy hormones...). But there were also plenty of passages that made me literally laugh out loud with their hilarity. This is one of the many things I love about John Green: he can both reduce me to tears and make me snort with laughter, all inside 10 pages.
Hazel shares her favorite book, An Imperial Affliction, with Augustus, and the two of them embark on a mission to contact its reclusive author in an effort to find out what happens to the characters after the story's abrupt end. And I really can't say more than that without ruining this fantastic story.
A note on the origin of the title: at one point, Augustus writes to that reclusive author about his relationship with Hazel, and this is part of the response that he receives:
"Were she better or you sicker, then the stars would not be so terribly crossed, but it is the nature of stars to cross, and never was Shakespeare more wrong than when he had Cassius note, 'The fault, dear Brutus, is not in our stars / But in ourselves.' Easy enough to say when you're a Roman nobleman (or Shakespeare!), but there is no shortage of fault to be found amid our stars."
For all my Indy friends, you might also appreciate that this book is set in Indianapolis, and basically every landmark is totally distinguishable, right on down to a gas station at 86th and Ditch.
In short, go. Go get this book now and read it immediately. And if you like this one (or if all the copies are checked out at your local library), pick up one of John Green's other books as well (Looking for Alaska, An Abundance of Katherines, or Paper Towns, or Will Grayson, Will Grayson, which he co-wrote with David Levithan). I love, love, love them all. Not to be impatient or anything, but when is his next one coming out??