The President of the United States is the Commander in Chief, who is responsible for all final decisions. The Secretary of the Department of Defense (DoD) has control over the military and each branch - except the Coast Guard, which is under the Dept. of Homeland Security. With over 2 million civilian and military employees, the DoD is the world's largest "company."
The profession of soldiering as part of a military is older than recorded history itself. Some of the most enduring images of the classical antiquity portray the power and feats of its military leaders. The Battle of Kadesh in 1274 BC was one of the defining points of Pharaoh Ramses II's reign, and is celebrated in bas-relief on his monuments. A thousand years later, the first emperor of unified China, Qin Shi Huang, was so determined to impress the gods with his military might, he was buried with an army of terracotta soldiers. The Romans were dedicated to military matters, leaving to posterity many treatises and writings, as well as a large number of lavishly carved triumphal arches and victory columns.
This continued in the 19th century, with publications like Punch in the British Empire and Le Père Duchesne in France, poking fun at the military establishment. This extended to media other print also. An enduring example is the Major-General's Song from the Gilbert and Sullivan light opera, The Pirates of Penzance, where a senior army officer is satirised for his enormous fund of irrelevant knowledge.
Personnel may be recruited or conscripted, depending on the system chosen by the state. Most military personnel are males; the minority proportion of female personnel varyies internationally (approximately 3% in India, 10% in the UK, 13% in Sweden, 16% in the US, and 27% in South Africa). While two-thirds of states now recruit or conscript only adults, as of 2017 50 states still relied partly on children under the age of 18 (usually aged 16 or 17) to staff their armed forces.
The history of the U.S. Armed Forces dates to 14 June 1775, with the creation of the Continental Army, even before the Declaration of Independence marked the establishment of the United States. The Continental Navy, established on 13 October 1775, and Continental Marines, established on 10 November 1775, were created in close succession by the Second Continental Congress in order to defend the new nation against the British Empire in the American Revolutionary War.
Your ASVAB scores determine what jobs you will qualify for in the military. But before you embarrass yourself in front of active duty service members, know that a job in the Army and the Marine Corps is called an MOS, which is an acronym for Military Occupational Specialty. In the Air Force, jobs are called AFSC – Air Force Specialty Code. In the Navy they are known as an NEC - Navy Enlisted Classification and the Coast Guard, jobs are called ratings, or rate for short.