I’ve been watching the YouTube channel John Green shares with his brother Hank, Vlogbrothers, for about six years now. It’s a channel I would recommend to almost anyone, provided they have a sense of humour, a desire to make the world a better place, and a propensity to think about things. I have great respect for John so, as with his 2012 novel The Fault in Our Stars, I pre-ordered Turtles All the Way Down with high expectations and I was not disappointed.

In many ways this is a book I have wanted to read for years; a stark and realistic portrayal of what it is like to live with a debilitating mental illness, specifically obsessive compulsive disorder. Aza is a teenage girl like most others. She has friends, crushes, and homework. However, she also has an obsession with infection which can intrude upon her consciousness at any given moment. She has a compulsion to keep checking a cut on her finger for infection, including re-opening it every time it heals, obviously making the chances of infection much higher. This well-demonstrates the irrationality of such compulsions, as does her later, more worrying need to wash out her mouth and insides with hand sanitiser, clearly an activity much more likely to cause harm to her than the thing she actually fears. Such a brutally honest account of OCD is to be treasured due to its rarity. The popular image of the disorder as a quirky character trait involving only a desire for cleanliness and order is very damaging to those who know from experience just how dangerous and incapacitating it can be.

Aside from its theme of mental health is that of personhood. The question of what makes a person is asked in many ways throughout the book. Is Chewbacca of Star Wars fame a person? Daisy certainly thinks so. If Aza is made up of more bacteria cells than her own cells (which everybody is), is her body really her own? If her thoughts seem to come from outside herself and force her into actions over which she’s not fully in control, is her mind really her own? The book continues down this line of questioning by having its characters talk about how a person doesn’t wield power but is wielded by it; likewise, people do not spend money but are spent by it. John Green has been criticised before for a lack of subtlety (or, at least, I know he has criticised himself in this way) and, indeed, he is rather direct in his approach to these themes, but this didn’t take away from my enjoyment of the book. For a young adult novel this approach to thematic writing is possibly preferable, giving teenagers a clear example of what it is for a book to handle themes and good practice in analysing them.

The plot concerns a disappeared millionaire whose corruption has been found out and his son, Davis, Aza’s love interest. Davis and Aza connect mostly through their very different problems. While neither can completely understand what the other is going through, they cling to one another for the empathy and human connection they crave. Their romance, like the rest of the book, is not in any way idealised and does not end how you might expect. I was able to predict the beats of the story fairly easily, but that’s more a strength of the writing than a weakness, as John showcases a practised understanding of story-telling.

The biggest criticism of John with which I can agree is that his teens are often unbelievably well-read and hyper-intellectual. While it’s true that there are teenagers out there writing great poetry and quoting classic literature, it makes for a slightly less believable novel. However, the raised intellectualism of the main characters fits quite well with the contemplative nature of Turtles All the Way Down, and with John Green books in general. This book’s brutally honest treatment of mental health and grief also effectively combats any problems of believability.

The last couple of pages of this book are my favourite, in which grown-up Aza briefly relates how life will go on for her after the story finishes. It is here that John Green’s own up-and-down experience with obsessive compulsive disorder powerfully shines through. It demonstrates that mental health is not necessarily a straightforward progression from getting ill to being cured forever, but a life-long condition which may impact upon a person’s life to different extents for the rest of it. Despite this, it is hopeful. It says that people such as Aza and John can have everything a healthy person can – love, a family, a career, a best friend – even if sometimes they will be too ill to manage it all on their own. This is ultimately very powerful. It seems almost as if John Green himself is talking at this point, reassuring himself as much as Aza and the reader.

Although this is a book aimed towards teenagers, it pulls no punches in its treatment of mental health. It also displays a surprising maturity in its handling of relationships, in all their forms. I would therefore recommend this book regardless of age. It took John five years to publish this book after his last one. We can only hope that in another five years we may get another gem like this.