Doesn't it look like an excellent summer read? As the cover states, it's a summer vacation story featuring four sisters, their neighbor, a dog, a teenage gardner and two bunnies.
If I had children, I would make them read this book. It follows a familiar story: an unhappy, lonely boy finds adventure/happiness/courage because of the friendship of four sisters. Jeanne Birdsall does a great job of making the four Penderwick sisters unique. It was funny, cute and evokes a child's summer perfectly.
The book is Birdsall's first novel but it won 10 awards (very impressive!). Her second book is The Penderwicks on Gardam Street.