Not as good as it probably used to be.
This book was probably great for its time (1972). I think it's a bit outdated in execution, although the message still resonates today.
A little boy named William wants a doll that he can play with, a baby doll with eyes that open and close, and he wants to treat it like a baby and wake it up in the morning and feed it and things like that. His brother tells him, "Don't be a creep!" (Which, today, is just a weird thing to say in that situation. Has the definition of "creep" really changed that much since the 1970s? I guess we would use something like 'freak' in the same sense now.) The boy next door calls William a sissy. William's father gives him a basketball and teaches him how to play. He learns how to play well and has fun, but he still wants a doll. So his father gives him an electric train and sets it up. He enjoys it as well, but it doesn't stop him from wanting a doll. Finally, his grandmother comes to visit. He mentions to her on a walk that he wants a doll. She says, "Wonderful!" He responds in confusion, explaining that everybody else seems to think dolls are not for boys. She replies, "Nonsense," and they go and get a doll, which William loves. "But his father was upset," the book continues. "He's a boy! ....Why does he need a doll?" And the grandmother replies, 'So that he can practice being a father.'
I saw a comic about a year ago that sums this up better than the book. (It's here, at Maximumble, #480.) "You can't give your son a baby doll. That's a girl's toy!" "Why?" "When he grows up he might be... you know..." "A dad?" As the panel zooms out, showing both of the adults bottle-feeding babies. It's still a problem today, discouraging the nurturing side of boys for fear of them being 'feminine,' but performing a complete 180 when they have children, suddenly expecting them to have fully developed that side of themselves.
At the end of the book, the grandmother even chastises the father, pointing out that William will make a great father, and that he might even get his son what he wants, such as a doll. And then the book suddenly stops.
It's got a good message, one that is sadly still relevant today. But it doesn't go into enough detail about the other characters in the book, and they don't seem to learn anything. William isn't even given much of a chance to react to getting the doll, or his father's reaction to it. It doesn't tell the whole story, only a brief snippet.
In 1972, this sort of thing must have been groundbreaking. But now, it doesn't go far enough. Preventing boys from doing anything stereotypically feminine is sexist against males and females alike. Boys should be allowed to do whatever they want, without being stigmatized, or having their sexual orientation assumed. We should be advanced enough as a society to realize that whether boys do something like play with dolls has no impact on their sexual orientation. (And, just to make things extremely clear, all sexual orientations are absolutely valid and normal. I don't want to imply otherwise.) If a boy is straight, playing with a doll won't cause him to become gay. If a boy is gay, preventing him from playing with a doll won't cause him to become straight.
And, on top of that, there is the clear implication that 'feminine' equates to 'lesser,' just as 'woman's work' is 'beneath' a man, being nurturing is a 'weakness.'
At any rate, it's not a bad book. It's decent. It's just that it could be a lot better, and there are better books that have been written in the past four decades. "Teddy's Favorite Toy" addresses the topic of boys playing with dolls in an excellent way-- by not addressing it. Teddy's favorite toy happens to be a doll, but nobody takes issue with that or makes fun of him or anything; the story is about him losing the doll and being reunited with it. And that's the kind of book that we need to help overcome prejudice and stereotypes. Books where things that wrongheaded people disagree with are incidental to the story. We don't dwell on them or question them, they're just facts. But this book was at the beginning of that, and it deserves some historical credit for that.