Retired Navy SEAL Task Unit Bruiser commander Jocko Willink. Courtesy of Jocko Willink and Leif Babin Jocko Willink is the retired commander of the most highly decorated special-operations unit of the Iraq War: US Navy SEAL Team Three Task Unit Bruiser, which served in the 2006 Battle of Ramadi.

In his new book, "Extreme Ownership: How US Navy SEALs Lead and Win," cowritten with his former platoon commander, Leif Babin, he and Babin explain the lessons learned in combat that they've taught to corporate clients for the past four years in their leadership-consultancy firm, Echelon Front.

Willink writes that he realized during his 20 years as a SEAL that, "Just as discipline and freedom are opposing forces that must be balanced, leadership requires finding the equilibrium in the dichotomy of many seemingly contradictory qualities between one extreme and another." By being aware of these seeming contradictions, a leader can "more easily balance the opposing forces and lead with maximum effectiveness."

Here are the 12 main dichotomies of leadership Willink identifies as traits every effective leader should have.