Assigning a name to a particular visitor / IP

Hello,
could anyone please advise me if it is possible to assign a unique name to a particular visitor or IP address? I’ve tried looking on the FAQ but can’t come up with anything.

I’d like to assign a name to my client so that I can quickly see from the visitors report if he is accessing the site rather than looking for his particular IP address.

Thanks for the help!
Michael

You can use Custom Variables with scope=visit

Now few years later, you should be using instead: User ID for setting your name/user id.

If you need to set even more dimensions / metadata to your users / visitors, use Custom Dimensions: Custom Dimensions - Analytics Platform - Piwik