An O-4 is a strange military bird. Majors are no longer “one of the boys.” They’re middle management. They’re the adult supervision. Making major is like going from single-A baseball to AAA. It’s kind of a big deal, but you’re still not in the major leagues just yet. Making captain requires a pulse; making major requires a functional cerebellum. It’s the stage when officers either stall out and crash, career-wise, or set themselves up for reaching the next level. Because of this, it doesn’t necessarily make once normal individuals into lobotomized morons, but it often reveals the moron inside. Promotion to major breaks up the once mighty pack of company-grade officer peers into several distinct breeds, each with unique characteristics. Here’s Task & Purpose’s illustrated guide to the six types of majors you find across the military.