Quentin is a morose young man whose life looks flat, boring and grey, especially when compared to the lives of the children in his favorite fantasy novel series. But when he's offered a place at Brakebill's, a college for magical instruction, he discovers his own aptitude for magic, and learns that magic doesn't fill the hole that makes him so depressed. Even when he and his friends discover the portal into the magical world of the fantasy novels, he can't seem to find his happiness. But, he learns, that's the point--you are all you've got, and your happiness is your own responsibility. 
 It's Harry Potter meets The Chronicles of Narnia meets A Catcher in the Rye, and the synopsis I've written here does not remotely do the book justice. It's a thematically complicated work that tackles huge questions of childhood, adulthood, fantasy, reality, happiness, monstrosity, and theology. Grossman seems equal parts understanding of the role fantasy (especially portal-fantasy) plays in the childhood imagination and cynical about how long people hold on to those fantasies. What makes you happy and fulfilled as a child, Grossman seems to say, can't and shouldn't make you happy and fulfilled as an adult. That's immature and regressive and no help to anybody. Those who hold onto their childhoods for too long become monsters, destroying the very fantasy land they didn't want to leave. 
 And yet, Grossman does not let reality off the hook, either. Reality gives Quentin and his friends nothing of value, offering only hedonism and excess, not meaning or happiness. Quentin longs to escape first to Brakebill's, then to Fillory, because his life--filled with sex, drugs, alcohol, self-pity, and ennui--is miserable, but does not realize until he's there that these places do not solve his problems. He is the constant in his life, and thus he is the only one who can choose to be happy, yet he never quite gets there. (At least by the end he has honest-to-Aslan reasons to be unhappy and disconnected.) 
 There's so much going on in this book that boiling it down to "Harry Potter for adults" or "the cynical Chronicles of Narnia" barely touches the surface of what this book is and can mean if you really think while you're reading it. 
 The only real issue I had was that maybe too much happens in this book; I could easily see it being broken up into two, if only to give the Brakebill's half a bit more attention and time. As it was, Grossman rushed through Quentin's time at Brakebill's--the whole five years--at breakneck speed, and it felt like there was more to that world that we could have explored if given time.