Zoe and her best friend, Olivia, have always had Big Plans: They'll tour the world as prima ballerinas and live in a swanky Manhattan apartment (where they'll hang out with their fabulous boyfriends, of course). But when they're cut from the ballet company, their plans for the future evaporate. Suddenly, Zoe's dodging cheerleaders who want her and Olivia to go out for the squad, and Olivia's got a crush on Calvin Taylor, who Zoe can't stand. 

Zoe can't imagine anything worse happening . . . until Olivia gets sick. Really sick. Suddenly, not being able to dance is the least of their problems.

Olivia has always been the nice one, the happy-go-lucky one. Zoe has always been the snarky one, the look-on-the-dark-side one. But when your best friend is in the hospital, you better learn to step up fast. Now Zoe needs to put on a brave face and be the positive one. Even when Zoe isn't sure what to say. Even when Olivia misses months of school. Even when Zoe starts falling for Calvin.

The one thing that keeps Zoe moving forward is knowing that Olivia will beat this thing, and everything will go back to the way it was before. It has to. Because the alternative is too terrifying for Zoe to even imagine.

My opinion:

I know, that your thoughts are now "Oh no, not another book about cancer!", but I promise "Maybe one day" is different to other "cancer-books".

This time it's not a love story, but a story about friendship. Olivia and Zoe are best friends science they were little. When Olivia gets sick, Zoe wants to be all of her time near Olivia and help her through the treatment.
I like, that the story is written from Zoe's point of view, because so it's another perspective than in the most other books like that and the author shows the feelings from the person who's not ill himself.
The story is about the friendship between the two girls with all their ups and downs.
I'm not sure, what I should say about Zoe. In some moments I liked her but often I couldn't understand her actions and didn't like her, so I can't emphasize with her.
I liked Olivia more, but I think the reader get to know her too little.
Though I like the story about the friendship between Zoe and Olivia, I think it's a little bit unrealistic how often Zoe can visit her best friend even if there is only the family allowed to see her.
I can't say something about Melissa Kantor's stlye, because my English is not good enough to judge it.

Conclusion: "Maybe one day" is a lovely story about friendship, but I don't like the prtagonist realy and sometimes it's a bit unrealistic.

No rating, because I have too little experience with English Books.