the pronoun of WHO?

The pronoun "who" is a subjective pronoun, meaning it acts as the subject of a verb.

Here are some examples:

* Who is coming to the party?

* Who wrote that book?

* I know who you are.

"Who" can also be used as the object of a verb, but in this case, it would be followed by a preposition like "to" or "for":

* The book was written by who? (incorrect)

* The book was written by whom? (correct)

Let me know if you have any other questions!