Paranoid is the single from the self titled album, released in 1970. This wasn't the first Black Sabbath song that I learned, but its definitely the one I played the most growing up because it's got such an great and well known riff. Even if you aren't a fan of Black Sabbath, there's a good chance you've heard this song. It uses a basic power chord shape but breaks it up with hammer ons, so you'll have to be able to bar with your first finger and hammer on with your ring finger. This one's a great song to learn standard rock guitar techniques because it uses a lot of 8th note palm muting and chord hits to emphasize the melody. The solo is pretty much all pentatonic but it has very melodic qualities and is a prime example of getting a lot of mileage of just a few small positions. This is something that's really important to get good at because it emphasizes the musicality of your playing instead of just playing quickly.