In the days before mass produced children's books there were children's books that could still stray outside the lines, and present topical subject matter.
Such a book is Oh Honestly, Angela; by Nancy K. Robinson. Despite the fact, or because of the fact, that the goings on are not as white washed as in the later chidren's books series, this book still manages to be more sweet and moralizing (in a good way). And despite, or because of the fact that the book is written for girls in the single digit range, it contains some very skillful (if brief) descriptions of social situations.
The book centers around 11 year old Tina, her 6 year old sister Angela, and their different ways of coping with The Meaning of Christmas. Tina wants to help the less fortunate at Christmas, but fears showing too much emotion around her rich, less compassionate friend. Angela wants to help the poor, too, even if it means giving up something dear to her.
All of this sounds corny, perhaps, but since this book isn't trying to be perfect, it ends up being a realistically told story about people trying to help others.