US army Lieutenant Colonel Jerry Brooks is on his third tour inIraq, but his mission has not been a typical one: as an army historian, he is charged with documenting the history of the Iraq war.

On his latest deployment, Brooks, 48, is the command historian for United States Forces - Iraq (USF-I), making him the army's top historian in the country.

He is still working to document the history of the conflict, with emphasis on American involvement, even as US forces are leaving Iraq. The US withdrawal is to be completed by year's end.

There were once 16 army historians in Iraq but that number is now down to two, Brooks said.

"My end product (will) be several quarterly histories that will be the basis of the histories that are written years from now -- maybe not by my sons but their children," Brooks, who is to be promoted to full colonel, told AFP.

The quarterly histories have not been published yet, and will generally not be until they are declassified -- a minimum of 10 years from now, he said.

However, "some unclassified portions can be pulled out before the 10-year mark," and "exceptions can be made and the declassification process started sooner," Brooks added.

He has also collected a huge amount of documents during his time in Iraq that "will be used to garner lessons learned for the military services as well as provide a single source of information regarding what was going on in Iraq during a particular time," he said.

For Brooks, there are three main strategic lessons to be drawn from the Iraq war: the need for contingency planning, having enough personnel and the importance of getting your message out.

"You have to plan, plan and continue to plan. You have to be ready to deal with any contingency that comes up," he said.

Second, "you have to make sure you have enough people to execute the mission and enough to have any unexpected issues."

And third, "information is a weapon. You have to get out in front of the enemy with your message."

Brooks recently led journalists on a tour of sites including a palace that once housed the top US generals in Iraq, another that served as the headquarters for various country-wide commands, and a secret prison in a bombed-out villa that once held Saddam Hussein.

During the tour, he rattled off facts ranging from information on the seventh-century Battle of Qadisiya between Arab forces and the Persian Sassanids, to Saddam's gardening habits while jailed.

Brooks, who was born in Pensacola, Florida, graduated from the Virginia Military Institute in 1985 with a bachelor's degree in history, and was commissioned as a second lieutenant in 1986.

In 1988, he entered the army reserve and studied at James Madison University, graduating with a master's in history in 1990.

Brooks, it turns out, became an army historian somewhat by accident.

After graduate school, he worked in insurance, but remained in the army reserves.

In 1995, he was sent to Fort Monroe in Virginia for annual reserve training, during which a colonel asked the assembled soldiers if any had a background in history. Brooks responded that he did.

He met with James Stensvaag, the command historian for the Training and Doctrine Command, who "had me fill out some paperwork and provide a copy of my master's thesis, which is on chemical warfare."

"In February of 1996, I received a letter telling me I was now designated an army historian," Brooks said.

"Five months later," he said, "I was in Bosnia working as a military historian."

"You could say that I stumbled into being a historian," Brooks said. "It was a very fortunate stumble for me."

Brooks then went into the inactive reserve and worked in insurance again, but was called up after the September 11, 2001 attacks and worked in the Pentagon's Joint History Office from December 2001 to December 2003.

There, he restored and preserved documents dating back to World War II, and "was also involved in the creation of detailed chronologies about the initial efforts in Afghanistan and Iraq," which US-led forces invaded in 2003, he said.

He first deployed to Iraq in July 2005 and served as the command historian for Multi-National Corps - Iraq (MNC-I) until June 2006.

He returned to Iraq from May 2008 to May 2009, first as MNC-I command historian and then as the command historian for Multi-National Force - Iraq, the predecessor of the current Iraq-wide command, USF-I, for the last three months of the deployment.

"My focus as a historian has been on the US efforts here in Iraq. During my first two tours here the key areas were the operational level actions," said Brooks.

He began his third deployment in May 2011, as command historian for USF-I.

"On the strategic level such as MNF-I and USF-I, I was focused on the actions of the commander and his staff," Brooks said, and also on operational summaries, to see what trends were developing.

"I was also busy doing document collection and interviewing. My document collection has been over one terabyte all three times," he said, referring to a measure of computer storage capacity.

From a personal standpoint, the third deployment was more difficult than the others, said Brooks, who did not have children when he was deployed before. His wife gave birth to his second son in August 2011, while he was in Iraq.

"I get to meet my son for the first time next month," he said.

Until then, Brooks will keep working on documenting events. "I will continue to gather information and documents up until the day I leave," he said.