'One' by Sarah Crossan

*This review will contain spoilers!* 

'When conjoined twins are separated, / it's deemed a success so / long as one of them lives. / For a while. / And that, / to me, / is the saddest thing / I know about how / people see us.' 

'One' tells the story of conjoined twins Grace and Tippi, written completely in the format of free verse.
After Grace suffers with the flu she develops cardiomyopathy and the weakened condition of her heart places strain on Tippi. Grace needs a heart transplant but isn't eligible due to being conjoined - the only option for the twins is to undergo a separation, or they will both die.
Being written in free verse, this book is over 400 pages but is an extremely fast read - I read it over a few sittings, but it probably only took me an hour in total. However, the speediness of the read does not detract from the emotional resonance: this book is going to stay with me for a very long time.
Before Grace and Tippi are diagnosed, they start going to high school for the first time in their lives. They're both understandably unsure about the move - they've been home schooled up to this point, and don't know how other students will respond to their condition - but when they join the school they quickly make friends with Yasmeen and Jon. Yasmeen suffers from HIV, having been infected by her mother while she was breastfeeding, so she understands exactly what it's like to have your death constantly hanging over your head. Jon quickly becomes Grace's focal point, as he treats her like an individual rather than part of a pair - it doesn't take long at all for her feelings for him to become more than friendly.
The plot of this novel definitely focuses upon their condition, but there are other things going on in their lives, which is something I appreciated. Too often, disabled characters are entirely defined by their condition, but with family issues and first loves, Grace and Tippi also live lives. I wasn't too sure about the romance between Grace and Jon (they seem to have a connection, but he sends love notes to Yasmeen just a few days before he starts kissing her, so I'm not sure what his agenda was...) but I was glad that there was some romance! I hate it when characters with differences are treated as though they're fundamentally unlovable, so it was nice to see that directly contradicted.
I'd never read a book about conjoined twins before (in fact my only previous encounter with conjoined twins in popular media was in 'American Horror Story: Freak Show', so you can imagine how those characters were represented...) and I appreciated Sarah ensuring they were completely individual people. Tippi is outgoing, strong-minded and addicted to caffeine: Grace is introverted, constantly worrying and always reading. The contrast between them made the connection between them even deeper, and I think it was a much more effective way of writing the characters - there's no way that you can get them confused, and it's just not possible to think of them as one person. I am not a conjoined twin, so I'll never know if the book was authentic, but I really enjoyed the attention to detail that went into every aspect of the construction of the characters.
The eventual decision to go through with the separation seemed very well researched: you can tell Sarah put a lot of love into this book. It's impossible not to feel empathetic towards the characters, and I constantly asked myself what I would do: if I'd been connected to someone my whole life, and one (or both) of us was likely to die, how would I cope? The fact that I had no answer for that made me feel even more emotional about Grace and Tippi's situation.
It was obvious that there wasn't going to be a happy ending for both characters, and I'm glad Sarah was realistic: it would have been unfeasible if both twins had survived after all of the warnings of low success rates. That didn't mean it broke my heart any less, though!
I really enjoyed this story being told in the free verse style, because it allowed uninhibited access to Grace's deepest thoughts and fears, while still including enough description to feel fully-rounded. Sometimes verse can be too minimalist, so it's very hard to feel connected to the setting, but Sarah's writing doesn't have this problem. Even though I read the book quickly I still took it all in - another thing that I've struggled with while reading free verse in the past.
This is the first book of Sarah's that I've read, and I'm certainly interested in trying out more. I've heard a lot of good things about her writing in the past, but now I've experienced it for myself I'm definitely more likely to try some of her previous novels.
If you're looking for something a bit different, I'd highly suggest this one: both for the format and for the subject matter.