This is more about that spankingly (spankably?) fresh heroine Harriet The Spy whose initial appearance occasioned all kinds of discussion among those who monitor juvenile literature; some thought she wasn't very "nice"; some even took the position that she was "sick."
In any case, in this sequel, Harriet is much less of a controversial character, and, sadly, she's lost lots of her sassy spriteliness. There are however occasional sequences which make the book, rather than Harriet, vaguely (very vaguely, by our standards) liable to censure. There is some consideration of religion with a valid if unorthodox conclusion—"It is a tool to get through life with. And if it works, it is a good tool. And if it don't work, it is a bad tool." Then there's a perfectly natural short discussion of that natural feminine phenomenon, menstruation, which occurs at this age but is seldom mentioned in juvenile fiction at this age level... Beyond that, The Long Secret is not as good, or perhaps cohesive, a story as the first one, partly because Harriet is subsidiary to her friend Beth Ellen. Beth Ellen's life is now disrupted by the reappearance of her delinquent but glamorous mother whom she hadn't seen in seven years. Her mother arrives, along with a new marital acquisition, and subjects Beth Ellen to Elizabeth Arden, the Bath & Tennis Club and a whole unwanted worldly sphere of life. In this case, Mother doesn't know best and is sent away, back to Europe. And this situation is not only an innovation but a dramatic reversal of the accepted "good family relationship" which usually obtains in books for and about the young... What about Harriet? She's busy too, trying to find out just who has been littering the community with threatening Biblical admonitions and the culprit will come as a surprise...
The scene is a small town on Long Island; the writing is not nearly as seriously funny as in the original; and even though Louise Fitzhugh is still well ahead of the field, the book is not as appealing as the first.