This is the 7871st most frequent Polish word.
milewskiego
"Milewskiego" is not a standalone word but a Polish surname in the genitive case, meaning "of Milewski."
Here, 'Milewskiego' is a possessive form (genitive case) of the proper noun 'Milewski', referring to someone's works.
Jestem wielkim fanem prac Milewskiego.
I am a big fan of Milewski's works.
In this case, 'Milewskiego' is used in the genitive case to indicate direction or context related to Mr. Milewski.
Rozmawiałem z panem Milewskiego o książce.
I talked with Mr. Milewski about the book.
Here, 'Milewskiego' functions as the direct object in the genitive case, referring to the person being acted upon.