Lifting weights. What is the right way ?

Ok so I currently lift heavy weights to failure ( which is between 6-10 reps). Since I lift weights to failure I only do 2 sets. I wish to increase muscle mass and strength. Should I do more than 2 sets? Should I be working to failure to acheive my goals? I have a book writeen by former Mr universe Mike Mentzer. According to him to build muscle mass you need to work to failure and you only need to do one set if you work to failure to stimulate muscles. He also says you need to rest between 4-7 days between each workout to improve muscle mass. Should I do what he says and is he right by what he says ?