Revolution by Jennifer Donnelly is my choice for "R" because I've been so impressed with her previous novels, The Tea Rose and The Winter Rose.
Revolution is the story of two girls, Andi and Alexandrine, who live 200 years apart. The setting of the novel is Paris, where current-day Andi is on winter break with her father and aspiring actress Alexandrine is caught up in the Revolution.
Andi finds Alexandrine's diary in an old guitar case and discovers that, even though the girls lived two centuries apart, they have something in common. Donnelly weaves a story where the past and the present become indistinguishable.
Revolution is noted as young adult fiction on goodreads, but so was Twilight and The Hunger Games. We all know what happened with those young adult novels. One thing I can guarantee, however, is the writing will be far superior to that of the Twilight series (I haven't read The Hunger Games so no comment there).
Click on the link below to watch a short interview of Jennifer Donnelly who talks about Revolution and, as a teaser, a fascinating discovery of evidence from the Revolution that touched her deeply.