He's one-fourth of the greatest hard rock band in history. Can you recognize this serious-looking young man from his yearbook photo?

We'll give you a few clues as to his identity to make this all go quicker and easier for you. As famous as our friend here would go on to be, it's safe to say he was the most under-appreciated member of his legendary group. Since their breakup, though, it's hard for any of them to match the impressive amount of territory he's covered working with some of music's biggest bands as both a producer and a performer. Think you know who we're talking about? Click here to find out if you're right!