This book is a guide to lively spoken American vocabulary. In an informal setting, this is exactly the kind of speech that is used. It can be cheerful, savory, allegorical, vulgar, etc., but never insipid and boring. These not always decent words are not taught in school, but every American has known them since childhood (just like we have their domestic counterparts). Without understanding them and not knowing the appropriateness of their use, you will never be able to look like one of the Americans and you will not understand most of their jokes. In short, no matter how much of a specialist and connoisseur of classical English you are, if you have no idea about the informal vocabulary listed in the dictionary, you will always be perceived in America as a “nerd,” “Chukchi,” or “teapot.” With corresponding chances of success.