quien

pron. whoever; whosoever

pron. who, whom

= who, whom, whoever.
Ex: The problem is to decide who to select as being mainly responsible.
Ex: The variety of reader places in a library adds interest to the interior but also provide for the many preferences of the users, some of whom seem to prefer a very busy location.
Ex: Whoever cataloged it at LC, and I'm willing to bet it happened elsewhere too, probably didn't get much beyond the dust jacket where there was a big clue about something special to the book.
----
* de quién sabe dónde = out of the woodwork.
* dime con quién andas y te diré quién eres = you are known by the company you keep.
* haz el bien y no mires a quién = cast your bread upon the waters.
* ¡mira quién habla! = look who's talking!.
* No importa lo que se conoce, sino a quién se conoce = It's not what you know, but who you know.
* quienes = whom.
* Quién es quién = Who's Who.
* quién iba a decir entonces que... = little did + Verbo + then that....
* quien mucho abarca poco aprieta = bite off more than + Pronombre + can chew.
* quien quiera peces que se moje el culo = you cannot make an omelette without breaking eggs.
* ¿quién sabe? = who knows?, who knows?.
* quién sabe lo que = who knows what.
* quién sabe qué = who knows what.
* quien siembra vientos recoge tempestades = as you sow, so shall you reap.
* ¡quién te lo iba a decir! = lo and behold!, lo!.
* salir de quién sabe dónde = come out of + the woodwork.
* ¡sálvese quien pueda! = the devil take the hindmost.