I've read so much info on scales, my head is spinning. It seems there are so many opinions on what scales should be learned that I'm confused. Can someone clarify what scales I should know for basic rock guitar. I like mostly older '70's and '80's stuff. I read I should learn major scales, then G major scales, then minor scales. I'm totally lost. I need a good comprehensive guide and I haven't found anything online or in the bookstore. HELP!