If you want to find who owns a phone number then you will need to do a reverse phone lookup. If the caller has used a landline then it is easy to find out who called. Just go to White Pages and you will find a reverse lookup box right there on the front page. If the called used a cell phone then finding out who called isn't quite so easy. You can try using your favorite search engine. Sometimes people leave their contact details online - maybe on their business website or a social network. If that doesn't help you then you will need to find a reliable, reverse phone lookup site.