Parents' Guide to Turtles All the Way Down

John Green delves deeper into the dark reaches of the teenage brain than ever before, creating a remarkable if occasionally hard-to-read story about a girl living with anxiety and OCD. While neither the protagonist nor the simple plot is as initially engaging as those in The Fault in Our Stars or Paper Towns, the story takes off once Aza rediscovers Davis. They're both half-orphaned and lost, but for different reasons. An avid astronomer, Davis looks up to the stars, whereas Aza concentrates on her self -- or selves, since she's focused on her body as a biodome for microorganisms (the body being roughly 10 percent human and 90 percent microbial). Green brings them together in a sweetly romantic way, but the romance is somewhat doomed, considering Aza's myriad neuroses (kissing, while initially pleasant, turns sour once the intrusive thoughts about the billions of bacteria they've shared begin).

For a book less than 300 pages long, Turtles All the Way Down requires a lot of unpacking and invites the reader to think, think, think about everything from mental illness to first love to the intricacies of Star Wars mythology. Like Aza's unique name (from A to Z and back again), there are endless possibilities for conversation points stemming from Green's themes. There are also extended therapy sessions, mini-lessons on the biological importance of the tuatara (a nearly extinct lizard-like creature that lives past 150 years and is actually more like a dinosaur than a lizard), and a great deal of existential angst. Green inserts gentle doses of humor, usually courtesy of Aza's vivacious best friend Daisy (who writes Star Wars fanfiction as a hobby), but this is ultimately a dark book about the trappings of mental illness. It also has one of the most memorable endings in young adult literature. Green's books aren't about happily ever afters but about the hope and love of moving forward, no matter how difficult that might seem.