When the author was asked what kind of books he considers - entertaining and educational or educational, Mikhail Goldenkov replied that he considers them as a kind of “first aid kit” for the domestic teaching of English. Indeed, it is as difficult to do without them when learning English as it is to go on a long hike without iodine and bandages. Readers know this and are happy to take into their luggage M. Goldenkov’s books “The Basics of English Slang and Business Correspondence” (1995), “Cool English (Cool English)” (1996). “CAUTION! NOT DOG!” is a new, more meaningful work by the author, in which he introduces the reader to the language of the American street, the subtleties of translation and the peculiarities of colloquial vocabulary. The book is necessary for everyone who wants to truly know modern English. It is supplemented by: Business English - the basics of business correspondence, as well as a unique dictionary of American slang idioms and catchphrases.