Apparating

[Cassandra Claire]

No: HPFGUIDX 3252

I apologize if someone has asked this question before, but I was 
wondering about Apparating. Can a wizard simply Apparate himself 
wherever he likes, whenever he likes? I know there are splinching 
issues, but what I'm wondering is: can you only apparate to places 
you've already been, or places you somehow have been given the 
'coordinates' to, or can you Apparate anywhere, even to a place
you've never seen or been before? If so, that seems somehow 
too...easy.

Any thoughts?