The Door to Door Bookstore is described as a feel good book about books and friendship and that sums up Carsten Henn's novel.
From the cover:
Small town German bookseller Carl Kollhoff delivers his books to special customers in the evening hours after closing time, walking through the picturesque alleys of the city. When Kollhoff unexpectedly loses his job, it takes the power of books and a nine year old girl to make his customers find the courage to rebuild their bonds with each other.