Can't remember why I wanted to read this but I needed a "light" book after reading a rather heavy one. It's what it says on the tin: table manners in the modern world. Covering everything how to eat certain items to how to handle different types of gatherings to when it's okay to use your devices, etc., this can be a handy guide.
That said, how helpful this is to you will probably vary on what you already know, where you are eating, etc. If you're someone who has probably navigated similar gatherings I'm not sure you'd get much out of this. But if you're say a graduate (high school, college) who has to navigate the non-school world of parties, gatherings, etc., someone who is new to the US (the author lives in Mexico and while I'm not very familiar with non-US dining customs there is a section on tipping, doggie bags, etc. that I don't think are very common outside of the US) and so forth.
That's about it. It's a relatively short book so it'd probably make a really good graduation/going away gift. Would recommend the library otherwise, unless you need a brush up.