During the surge in Iraq, we were able to roll back the tide of al-Qaeda and associated insurgents because we succeeded in mobilizing Iraqis - especially Sunni Arabs - to join us in fighting against the largely Sunni extremist networks in their midst.

People often ask, why aren't you reading about what it is you're working on right now? And the truth is, you only get three pages a night before your eyelids close.

The Germans have done wonderful work. Not long ago, a German battle group battalion conducted a very impressive counterinsurgency operation in a portion of Baghlan province. I think these are the first counterinsurgency operations conducted by any German element after World War II. And they did a very impressive job.

President Obama has said that our aspirations should be realistic. We are not going to turn one of the poorest countries in the world, that was plunged into 30 years of war, into an advanced, industrialized, Western-style democracy. What we want to achieve is Afghanistan's capacity to secure and govern itself.

Well, the oil, the oil spot, if you will, is a, is a term in counterinsurgency literature that connotes a peaceful area, secure area. So what you're trying to do is to always extend that, to push that out.

We all have to strive to learn what motivates us, learn from our experiences, and what feels right and what feels wrong. There's a strong component over the years to having formal processes that help to identify lessons that need to be learned, and actions that need to be taken. In other words, how do you find the big idea?

We need to learn from our experiences and take responsibilities for our actions and drive on.

When I was commander of Central Command, obviously we were very concerned about the developments in Yemen, the developments in Somalia and elsewhere, in Africa and so forth. But the al Qaeda senior leadership is under unprecedented pressure.

I'm heartened that, for the first time, we're seeing some of the Internet Service Providers and the social media sites taking action against the Islamic State. That's the kind of initiative that can very, very much augment on an industrial scale what the government is trying to do.

There aren't always a hell of a lot of absolutely right answers out there.

The proximate cause of Iraq's unraveling was the increasing authoritarian, sectarian, and corrupt conduct of the Iraqi government and its leader after the departure of the last U.S. combat forces in 2011.

You have to keep on disrupting. If you let up the pressure, then al-Qaeda senior leadership will come back.

The formulation of sound national policy requires finding the right overarching concepts.

It wasn't just Shia that would go to Tehran and see the commander of the Quds Force and others and the legitimate government leaders. It was also Kurdish leaders and Sunni Arabs who would even link up with Qassim Suleimani, the commander of the Quds Force - maybe not in Tehran but in Turkey or somewhere else.

Needless to say, it was the greatest of privileges to serve with the selfless men and women - Iraqi and American and those of our coalition partners, civilian as well as military - who did the hard, dangerous work of the surge. There seldom was an easy period; each day was tough.

Central to achieving progress in Afghanistan - and to setting the conditions necessary to transition security tasks from the international community to the Afghan government - is increasing the size and capability of ANSF.

All Americans should take great pride in the men and women serving our nation in Iraq and in the courage, determination, resilience and initiative they demonstrate each and every day. It remains the greatest of honors to soldier with them.

Counter-insurgency, as you know, is a roller-coaster affair.

Folks really need to be very cautious about overanalyzing or overparsing what I've said to this reporter or that reporter.

The situation in Iraq was dire at the end of 2006, when President George W. Bush decided to implement the surge and selected me to command it. Indeed, when I returned to Baghdad in early February 2007, I found the conditions there to be even worse than I had expected.

I refuse to use terms like 'optimist' or 'pessimist' and instead prefer 'realist.'

But clearly, this is what this is about. It's about pushing the security bubble out. It's about rooting out every last guy, so that there's not even somebody who can fire a single, solitary RPG round from some little qalat out here.

The biggest of the big ideas that guided the strategy during the surge was explicit recognition that the most important terrain in the campaign in Iraq was the human terrain - the people - and our most important mission was to improve their security.

Iraq is a country I came to know well and the place where I spent some of the most consequential years of my life.