“Middle grade” isn’t a genre. It’s a recommended age level. Which is just about the only thing these titles have in common. Half a Chance is a slice-of-life summertime story about a girl whose family moves a lot and her love for photography. (Adored the “scavenger hunt” style photography challenge.) In When You Reach Me, Miranda tries to make sense of the things that are going on around her—the notes, on-again-off-again friends, who likes who, and the best way to win at a game show. And At the Bottom of the World is the first book in the Jack and the Geniuses series, which succeeds in making science fun. (Makes sense, considering Bill Nye is part of the project.)