As I read this book I wondered whether it was written for girls or simply children in general to help them understand the way babies grow into children. The theme that seems to run through this story is how the protagonist, Jenny, is waiting for her baby brother, Jonathon, to reach the stage when he can be a friend, namely that he can communicate with her and can walk and do the same things that she can do. A part of me suggests that we should not base our friendships upon people's abilities but rather that we should simply be friendly rather than determining when somebody can be a friend.
The other thing, and yes I do understand that this is a children's book, is that this seems to assume that every family is a perfect family and that every child grows up to be a healthy and intelligent child. This does not actually always happen. I remember that when I was a child I was waiting for my brother to reach that stage when we could communicate (in my mind, to stop being silly and saying silly things) but that was never going to happen because he was born with an inability to be able to communicate effectively with other people. As for my sister, when she reached that age we ended up fighting.
Please don't that this as a criticism of the book though, even though the story in this book does not really appeal to me (but then I have noticed that the Little Golden Books are of a lesser quality than the Dr Suess books – I still quite like the Dr Suess books, and I can say that because I have been reading through them as I sit here board out of my brains in Adelaide – okay not board, because I can read my brother's children's books and add them to my Goodreads list).