Our Army is the center of gravity for the U.S. military - and this center includes the Guard and Reserves.

It is the best and most combat-hardened Army that the nation has ever known - indeed, the world has ever known. And we must do all we can to make sure it stays that way.

Let me take you through some of the things I have learned about our Army, which we all serve. Some of these things might surprise you, most probably will not, but I thought you might be interested in how this Sailor has come to see it.

The first thing I learned about the Army is hooah.

There are 1,000 or 10,000 or 100,000 different ways to say hooah. But I learned that it is more than just a battle cry; it is a way of life. It says that you will never quit, never surrender, never leave your buddy. It says that you are proud of the hardships you have endured because there is deep meaning in every one of them.

Go stand atop one of those hills in the Korengal Valley in Afghanistan, where I was last February and July, with paratroopers assigned to the 173d Airborne Brigade Combat Team. Look around at the utter desolation of the place and the spartan conditions that these young people are living in. You cannot help but come back a little thick in the throat.

I awarded a Silver Star to a young officer there, Capt. Greg Ambrosia, who placed himself in the line of fire to direct his men to safety. I pinned on some Bronze Stars, Commendation Medals, and Purple Hearts as well. These troops had been out there 14 months and seen a lot of tough fighting. They lost a lot of good Soldiers. We often forget the impact of war on those who were alongside our fallen. That loss impacts them for the rest of their lives.

When those Soldiers yelled "Hooah!" after the ceremony, I understood that it was not because they were proud of their new medals; it was because they were proud of the difference they knew they were making together, as a team-as an Army.

The second thing I have learned is that our Army has become a world-class counterinsurgency force in an extraordinarily short time.

In Iraq, I walked down the streets of Sadr City, and visited an outpost in Mosul. These were places where, just a few weeks before, we could not have visited at all. Al Qaeda is clearly on the run in Iraq, and the surge and Anbar Awakening and even Muqtada al Sadr's ceasefire all helped to make that happen. But what really turned it around was the counterinsurgency tactics that our troops embraced and perfected.

Think about it: As late as the winter of 2007, when President Bush announced the surge, attacks were averaging nearly 180 a day, the highest level since major combat operations ended. A new national intelligence estimate predicted that Iraqi leaders would be hard pressed to reconcile over the next year and a half.

But look where we are now. Our commitment to counterinsurgency warfare worked. That meant sharing risk with the Iraqis, which in turn meant a whole lot of courage on the part of our Soldiers. Yet they prevailed because they learned, adapted, and most of all believed.

Third, I learned that it is irresponsible to neglect the continual improvement of our conventional capabilities. I was struck during one of my first visits as chairman to an Army base - Fort Sill - by how few young artillery officers had earned their basic qualifications because they had so often deployed outside their skill set.

Now, as the chief of Naval Operations who deployed upwards of 12,000 Sailors to work on the ground in the U.S. Central Command theater, I understand the benefit for people to develop themselves. We need more balance in the way we think, train, and resource ourselves. Very real threats still exist from regional powers who possess robust conventional and, in some cases, nuclear capabilities. We must restore some of the more conventional and expeditionary expertise that we will require in the uncertain years ahead.

It is difficult to modernize while fighting a war. But there is also an argument that a combat footing generates the energy and sense of urgency that allow us to meet the pace of change. The essential truth is that we are at war - and it is a war that is moving at lightning speed.

And that brings me to my fourth observation: our peacetime processes are not adapted to a wartime reality. We simply have not kept pace with the demands that this war requires of our wounded, fallen, and their families.

Some wounded servicemembers are waiting too long to receive disability ratings and transition out of the military, leaving them and their families in limbo. Indeed, servicemembers tell me that their most precious resource is time. They want their lives back. They want to move on.

I know that we have launched a pilot program with the Department of Veterans Affairs designed to streamline the transition process, but we are still not moving quickly enough. And I hope that we are able to expand it as rapidly as possible.

Recent studies suggest that as many as 20 percent of today's troops may suffer from post-traumatic stress brought on by combat in Iraq and Afghanistan. Many are understandably wary of the stigma attached to mental health issues - a problem we can alleviate by making everyone undergo screening, so no one has to raise his or her hand.

I recently had the chance to visit the VA hospital in Palo Alto, Calif., and talked with about 30 mostly active-duty PTS patients from every service. It bothered me to see what they had to go through just to get help - essentially bottoming out, like they were in an alcohol or a drug rehabilitation program.

The families of the fallen and the wounded never lost the American dream. They still want to work; they want to send their kids to school; they want to get an education; they want to own a piece of the rock. Indeed, they have earned it. And it is up to us to ensure that they get the chance.

Finally, I have learned that the Army, above all, is a learning organization. From rapid development and adaptation of doctrine, to command organization, to movement of brigade combat teams and modular headquarters, to the way people are promoted, the Army is constantly changing and adapting to meet the challenges of the day.

We are seeing people succeed, grow, and lead. We are seeing people unafraid to challenge assumptions or old ways. Our mid-grade noncommissioned officers and young captains love what they do. They have led in combat. They are remarkably resilient, and they do us all proud.

Junior officers and enlisted men and women need to know that it is right to question the direction of their service and seniors. In fact, they should be rewarded for it. That sort of feedback is healthy, and it foments the kind of change we need. As General George Marshall once quipped, "Soldiers are intelligent. Give them the bare tree; let them supply the leaves."

I have certainly seen the forest for the trees here, and have learned a lot about the Army. Most importantly, I have learned from the Army.

(Adm. Michael G. Mullen serves as chairman of the Joint Chiefs of Staff. This article first appeared in the Joint Force Quarterly magazine, First Quarter 2009 edition.)