Modern Dutch has largely abandoned the old genitive case. Where English uses “‘s” (John’s book) or “of” (the book of John), Dutch primarily uses van: “het boek van Jan” (Jan’s book), “de deur van het huis” (the door of the house). This van construction is universal, simple, and consistent across all nouns and articles.
The old genitive -s ending survives in specific contexts. With proper names: Jans boek (Jan’s book), Maries huis (Marie’s house). In fixed expressions and compounds: ‘s morgens (in the morning), ‘s avonds (in the evening), des te beter (all the better). These fossilized genitive forms appear in formal writing and set phrases — you will encounter them in texts even though they are rarely produced in everyday speech.
The possessive construction van + pronoun expresses “of mine,” “of yours,” etc.: “een vriend van mij” (a friend of mine). This construction is more common in Dutch than the equivalent in English and sounds more natural than using the possessive adjective alone in many contexts. Understanding the van-genitive thoroughly makes reading Dutch literature, legal texts, and formal documents significantly easier.