Judy Blume books were required reading for teenagers in the early 90s. She was kind of our Jacqueline Wilson. Some of the books were quite controversial as they talk explicitly about puberty and early sexual awakening. I don’t know if they would be too dated for kids to read now but since most of the information we got about sex came from each other, Judy Blume’s books did us a lot of good I think.
This particular one is about a boy growing up, he uses the binoculars (pictured) to spy on the girl who lives opposite when she gets undressed!