The amazing sound of hair metal has never been bigger! Or at least that’s what the producers of Rock of Ages are hoping as the Tom Cruise movie gears up to open this Friday. The stage play has been a hit on Broadway, but it hasn’t exactly been playing to the intellectual elite. Rock of Ages will have to appeal to the ordinary folks who hopefully still want to hear film stars playing hits made famous by Journey, Poison, Twisted Sister, Bon Jovi, and more. The genre’s a joke to a lot of people, but still a guilty pleasure to others. Now here’s a quick primer on the historically important hair metal figures, along with some of the lesser lights whose hair deserved more time in the spotlight. Read, learn, and–most importantly–rock!