H.R. McMaster is a Brigadier general, United States Army, now moving to be a strategic adviser to General David Petraeus in the Afghanistan War (2001-). His first assignment as a general was Director, Concepts Development and Experimentation, Army Capabilities Integration Center, U.S. Army Training and Doctrine Command. Known both as a successful combat and counterinsurgency commander, he had been passed over twice for promotion to brigadier general, often a career-killing event. Some of the Army establishment were uncomfortable with his academic experience, including a best-selling book that resulted from his doctoral dissertation. General David Petraeus used McMaster as a strategic adviser in Iraq, and was on his second promotion board that awarded him his star. 
In June 2010, before Petraeus stepped down from United States Central Command to take direct control of the Afghan theater, W. Patrick Lang, calling the overall situation an impossible task, still suggested that "All right, let's give him Mattis, in my opinion, the best marine around now, as his deputy and lets give him McMaster as his chief of operations. Give McMaster a couple more stars. Why not?" Mattis, however, took Petraeus' old job at CENTCOM, and McMaster's role is still emerging.
While he made extremely effective use of high technology systems at 73 Easting, he has cautioned against too great a reliance on technology, especially in counterinsurgency. 
After his combat command, and while in fellowships, he commuted to Iraq as part of Petraeus' strategic advisory panel.
In the Name of God the Compassionate and Merciful
To the Courageous Men and Women of the 3d Armored Cavalry Regiment, who have changed the city of Tall’ Afar from a ghost town, in which terrorists spread death and destruction, to a secure city flourishing with life.
To the lion-hearts who liberated our city from the grasp of terrorists who were beheading men, women and children in the streets for many months.
To those who spread smiles on the faces of our children, and gave us restored hope, through their personal sacrifice and brave fighting, and gave new life to the city after hopelessness darkened our days, and stole our confidence in our ability to reestablish our city.
Our city was the main base of operations for Abu Mousab Al Zarqawi. The city was completely held hostage in the hands of his henchmen. Our schools, governmental services, businesses and offices were closed. Our streets were silent, and no one dared to walk them. Our people were barricaded in their homes out of fear; death awaited them around every corner. Terrorists occupied and controlled the only hospital in the city. Their savagery reached such a level that they stuffed the corpses of children with explosives and tossed them into the streets in order to kill grieving parents attempting to retrieve the bodies of their young. This was the situation of our city until God prepared and delivered unto them the courageous soldiers of the 3d Armored Cavalry Regiment, who liberated this city, ridding it of Zarqawi’s followers after harsh fighting, killing many terrorists, and forcing the remaining butchers to flee the city like rats to the surrounding areas, where the bravery of other 3d ACR soldiers in Sinjar, Rabiah, Zumar and Avgani finally destroyed them.
I have met many soldiers of the 3d Armored Cavalry Regiment; they are not only courageous men and women, but avenging angels sent by The God Himself to fight the evil of terrorism.
The leaders of this Regiment; COL McMaster, COL Armstrong, LTC Hickey, LTC Gibson, and LTC Reilly embody courage, strength, vision and wisdom. Officers and soldiers alike bristle with the confidence and character of knights in a bygone era. The mission they have accomplished, by means of a unique military operation, stands among the finest military feats to date in Operation Iraqi Freedom, and truly deserves to be studied in military science. This military operation was clean, with little collateral damage, despite the ferocity of the enemy. With the skill and precision of surgeons they dealt with the terrorist cancers in the city without causing unnecessary damage.
God bless this brave Regiment; God bless the families who dedicated these brave men and women. From the bottom of our hearts we thank the families. They have given us something we will never forget. To the families of those who have given their holy blood for our land, we all bow to you in reverence and to the souls of your loved ones. Their sacrifice was not in vain. They are not dead, but alive, and their souls hovering around us every second of every minute. They will never be forgotten for giving their precious lives. They have sacrificed that which is most valuable. We see them in the smile of every child, and in every flower growing in this land. Let America, their families, and the world be proud of their sacrifice for humanity and life.
Finally, no matter how much I write or speak about this brave Regiment, I haven’t the words to describe the courage of its officers and soldiers. I pray to God to grant happiness and health to these legendary heroes and their brave families.
NAJIM ABDULLAH ABID AL-JIBOURIMayor of Tall ‘Afar, Ninewa, Iraq 
He was the tactical commander at the Battle of 73 Easting, in which a reinforced armored cavalry troop completely destroyed an Iraqi tank brigade, without U.S. losses.
Academic and research
His doctoral dissertation in history became the book Dereliction of Duty: Lyndon Johnson, Robert McNamara, the Joint Chiefs of Staff, and the Lies that Led to Vietnam., a major work on decisionmaking during the Vietnam War, highly critical of the civilian leadership and the Joint Chiefs of Staff.
Between 2002 and 2003, he was a fellow at the Hoover Institution, 2002-2003
He is a member of the Council on Foreign Relations.
- "Petraeus Picks McMaster to Join Afghanistan Team", CBS News, 23 July 2010
- Fred Kaplan (21 November 2007), "Promoting Innovation: Can Gen. David Petraeus fix the Army's broken promotion system?", Slate
- W. Patrick Lang (24 June 2010), "What's At Stake In South-Central Asia?", National Journal
- Max Boot (4 August 2010), "How Petraeus Is Conducting Counterinsurgency in Afghanistan", Commentary (magazine)
- H.R. McMaster (July 2010), Chapter 4: NATO will only succeed if its platoons succeed: psychological and ethical preparations for counterinsurgency, in Christopher F. Schnaubelt, Complex Operations: NATO at War and at the Margins of War, Research Division, NATO Defense College
- Saluting the 3rd ACR, Mudville Gazette, 16 February 2006
- H. R. McMaster (1997), Dereliction of Duty : Johnson, McNamara, the Joint Chiefs of Staff, and the Lies That Led to Vietnam, HarperCollins, ISBN 0060187956