Shampoo: It seems like it should be the simplest step in hair care, yet contradictory advice about it seems to be coming out of everyone's ears. To clear things up, we approached Josh Rosebrook, celebrity hair stylist and creator of the ultra-pure, super-hard-working Josh Rosebrook line of hair care products. He has spent 17 years working on tresses and observing just what shampoo can do (or not do) to benefit both hair and scalp.