Okay kiddo, so you know when we learn good manners? Like saying "please" and "thank you", or covering our mouth when we cough, and not interrupting others when they're speaking? Well, Emily Post was a woman who wrote a book about good manners a long time ago, and people still use her advice today!
She wanted to help people be polite and respectful to each other, and her book has lots of tips on how to do that. Like, she tells us how to behave at dinner parties, or how to write a nice thank-you note, or how to dress appropriately for different events.
Emily Post also believed that good manners showed that a person had good character and made others feel welcomed and valued. And that's why her book on etiquette is still very popular even though it was written a really long time ago. Because being kind and courteous never goes out of style!