If not, I urge you to hurry to the young people's section of your local library or bookstore to become acquainted.
So far there are three books in the Penderwicks series written by Jeanne Birdsall. The first is called The Penderwicks: A Summer Tale of Four Sisters, Two Rabbits, and a Very Interesting Boy. The second is The Penderwicks on Gardam Street, and the third is The Penderwicks at Point Mouette.
The Penderwicks are four sisters, Rosalind, Skye, Jane, and Batty, who live with their widowed, professor father and a dog named Hound. The books are simply about the adventures they have and the people they come into contact with in their everyday life, whether it be at home, spending the summer at a cottage on a wealthy estate, or a two week vacation in Maine
These are some of the most charming, modern books I have read. I can't wait to read about more of their adventures, and really hope more books in the series will be coming soon.