A thoroughly enjoyable book. As typical with John Green, the story has a lot of heart and soul. 
 Like his other works, this book targets the young adult reader, specifically high school to college age. The way I figure it, you're picking it up because you're either at that age or were at some time in life. Therefore, I'd point out that the theme of the book relates to most anyone over the age of 13. Green addresses isolation, friendships, love, and loss in a story that hits home. 
 I like the way that John Green writes. His characters have their triumphs and they have their troubles. He opens them up, so they're not just a simple, two-dimensional being on a page left for the reader to interpret. And somehow he gets a lot across within just a couple hundred pages without being complicated. The ending wasn't quite what I had hoped for, but I bet most readers would be just fine with it.