Learn Hardcore Russian: У меня есть четыре книги.

Literally, the phrase breaks down as at me there is four books (“у” + genitive “меня” means “at me,” “есть” is “there is/are,” and “четыре книги” is “four books”). Idiomatically in English we say I have four books.

Why do we use У меня есть to express “to have,” instead of a verb like иметь?

Russian doesn’t use a direct equivalent of the English verb “to have” in everyday speech. Instead, possession is shown with the construction У + [genitive of the possessor] + есть. The verb иметь exists but sounds bookish or bureaucratic; native speakers virtually always say У меня есть rather than Я имею.

Can the verb есть be omitted? What happens if I just say У меня четыре книги?

Yes. In colloquial Russian you normally drop есть, so У меня четыре книги is perfectly natural and means exactly the same thing: I have four books. Including есть can add a slight emphasis on existence (e.g. contrasting with not having something).

Why is книги not in the nominative plural but in the genitive singular form?