Olive Marshmallow

“Why is my house full of fluffy, frilly, very pink things?” wonders a boy named Archie. He finds out soon enough, when Mommy (who appears to be a single parent) returns from the hospital with a baby sister named Olive, who Archie deems the spitting image of a marshmallow. Unlike most of Archie’s peers in the displacement canon, Archie has minimal pre-birth anxiety and takes to big brotherhood like he was, well, born to it: “Soon, life with Olive Marshmallow... became so much FUN!” writes British author-illustrator Saunders, showing Archie savoring the new companionship and even sitting down to tea with Olive and her dolls. Saunders never really establishes the cherubic Archie as the kind of boy with a girls-have-cooties mind-set, so his transformation into a loving sibling isn’t much of a turnabout; indeed, the lack of emotional speed bumps may strike readers as unlikely. In any case, there’s an admirable steely determination that drives these sunny, naïf drawings, filled with roundheaded, bright-eyed characters. Saunders simply assumes everything will turn out all right—and then delivers on it. Ages 3–6. (Mar.)