Dead lifting will strengthen the entire back and its surrounding muscles. In fact, the dead lift is the most effective exercise for building the core strength that supports all other major muscle groups.
Core strength (core pertaining to the central muscles of the body; lower back, glutes and the abdominal region) is a very important health component, in that it supports the body in almost every movement and position, and the dead lift is the key core strength building movement.
During the winter of 2008, my son and I left North Carolina to live in the mountains of Oregon for three months, while I trained for my first half marathon. It just so happened that due to the extreme weather conditions that specific winter, I was forced to utilize every muscle in my body while I ran long distances through snow, wind and extreme cold. Let's just say that I was in the best shape of my life. It must have showed on me, because as I sat in my son's favorite book store one day, after one of my longer runs, he started to sing a melody that he had made up called, "She's Got Mad Abs." I loved it. Well of course, I love him. But not the point. I have always been conscious of my core muscles since the first day I trained to become a Step Aerobics Instructor back in 1991. Posture is everything in those classes. Good form comes with great core strength. I believe that everything you do involves the core muscles (transverse abdominis, internal obliques, external obliques, rectus abdominis, hip abductors/adductors, hip flexors, and lumbar spine), and if they are weak, everything you do requires additional concentration on keeping the core muscles contracted and stabilized. So, while running outside, joining a Cycle class, or strength training in the gym, there are more productive ways of focusing on the core muscles leading to a healthier, happier body.