One, by Sarah Crossan

Grace and Tippi are literally as close as two sisters can be.  They're conjoined twins.  And while the doctors never expected them to live past their second year, they're now in their Junior year.  Their lives are full of special challenges, most notably their difficulty at fitting in, but they both have no desire to change.  With the help of two new friends (the wild Yasmeen and her friend Jon), the girls finally have a social life and (for Grace) a chance at something more.  But then tragedy strikes and the twins face a challenge for survival.

Written in free verse, the novel (despite its many pages) is a brisk read.  That verse isn't particularly stand out, but the subject matter is riveting.  It's not really a spoiler to say that it ends in heartbreak (the lives of conjoined twins are rarely happy ones) but Crossan tells their story with dignity and Grace's voice is compelling.  The classic gold standard for a novel for me is whether the book is readable, full of interesting and sympathetic characters, and whether I learn something from it (with bonus points for a weepy and life-affirming ending).  This novel delivers all of the above.