The Night Circus by Erin Morgenstern
The circus arrives without warning. No announcements precede it. It is simply there, when yesterday it was not. Within the black-and-white striped canvas tents is an utterly unique experience full of breathtaking amazements. It is called Le Cirque des Rêves, and it is only open at night.
But behind the scenes, a fierce competition is underway—a duel between two young magicians, Celia and Marco, who have been trained since childhood expressly for this purpose by their mercurial instructors. Unbeknownst to them, this is a game in which only one can be left standing, and the circus is but the stage for a remarkable battle of imagination and will. Despite themselves, however, Celia and Marco tumble headfirst into love—a deep, magical love that makes the lights flicker and the room grow warm whenever they so much as brush hands.
True love or not, the game must play out, and the fates of everyone involved, from the cast of extraordinary circus per­formers to the patrons, hang in the balance, suspended as precariously as the daring acrobats overhead.
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It may have taken a little while for this book to really capture my attention, maybe 100 pages or so, but once I hit that "point," the black and white text became a drug and I just could not get enough.  Two days later, I am still feeling the loss of the magic created by this story, ironically about magic!  It has everything you want in a novel - suspense, mystery, forbidden love, historical setting - and yet takes it to a new level of freshness through its whimsy, maintaining the fine balance of not too much romance or not too much unbelievable nonsense.  
While reading many of the chapters, especially later in the book,  I could envision the scene perfectly for how it could be portrayed in film.  The author's ability to generate characters to which you form a deep attachment and invest emotion, as well as her talent for creating imagery that sets your imagination free to just relax and let her do all the work for you is refreshing.
This book has been, unrightfully, compared to the Twilight series because many fans have latched on to it and spread its popularity via fan forums.  The maturity of the storyline and complexity of the characters, in my opinion, generate a sophistication beyond comparison with that simple, young adult vampire series.  There is, equally, no comparison to be made with another popular book set in a circus, Water For Elephants - a story that appears more "watered down" and unimaginative when put next to The Night Circus.
This book was recommended by a friend who also suggested Jenny Lawson's "Let's Pretend This Never Happened" that had me crying with laughter.  I'm going to have to get together with her soon and drag some more book ideas from her because she's 2 for 2 now!