The moment I started this book, I found it so difficult to put down again. It has an engaging pace, one that allows for slow moments in-between extreme bouts of action. It never felt like it was relying too much on exposition and let interactions carry on at a natural place. The world itself is so interesting, with magical tomes being living objects and librarians essentially acting as literal guardians of them and their contents. 

Elisabeth's tenacious personality never came off as grating nor did it propel her into doing rash thing just for the sake of it. Each of our leads have such enigmatic personalities that you just can't help but slowly fall in love with them all: Elisabeth, for said reason's above, Nathaniel's snark and rakish charm, and Silas' reserved but equally judgemental nature. Silas is probably the standout character, being a demon that everyone says is untrustworthy and only out for himself, but darn it you really can't help but love him for how loyal a friend and caretaker he is for Nathaniel. 

And that climax did an excellent job of escalating the action and peril while still giving a thematically and emotionally satisfying ending. Despite it being a standalone, I definitely wouldn't mind a continuation of some sort.