This book is a guide to lively spoken American vocabulary. In an unofficial setting, just such speech is used. She is cheerful, savory, allegorical, vulgar, etc., but never fresh and boring. These not always decent words are not taught at school, but every American has known them since childhood (like us - domestic counterparts). Without understanding them and not knowing the appropriateness of use, you will never be able to look your own among Americans, you will not understand most of their jokes. In a word, whatever you are a specialist and connoisseur of classical English, having no idea about the informal vocabulary given in the dictionary, you will always be perceived in America as a nerd, or a kettle. With appropriate chances of success.