Seeley Booth is a former sniper with the U.S. Army Rangers. He now works with the FBI and alongside the team led by Dr. Brennan.
At first, Booth was not happy to act as a liaison between the FBI and the Jeffersonian Institute. But he eventually developed personal and professional chemisty with Bones. They now with a top notch crime-fighting unit.
Booth is an ideal complement to Bones' speciality in science. He's intuitive and knows how to read people.