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 AFQT is often mistakenly called the “overall ASVAB score.” You commonly hear someone say, “I got a 67 on the ASVAB,” or “My ASVAB score was 92.” That’s not correct; it implies that the AFQT is derived from all nine subtests of the ASVAB, and it’s not. The AFQT score is computed from just four of the ASVAB subtests that measure your math and communicative ability.
Somewhat earlier, in medieval China, gunpowder had been invented, and was increasingly used by the military in combat. The use of gunpowder in the early vase-like mortars in Europe, and advanced versions of the long bow and cross bow, which all had armour-piercing arrowheads, that put an end to the dominance of the armoured knight. After the long bow, which required great skill and strength to use, the next most significant technological advance was the musket, which could be used effectively, with little training. In time, the successors to muskets and cannon, in the form of rifles and artillery, would become core battlefield technology.
Focusing Your Study - As you take more and more sample tests you begin to get a feel for the topics that you know well and the areas that you are weak on. Many students waste a lot of valuable study time by reviewing material that they are good at (often because it is easier or makes them feel better). The most effective way to study is to concentrate on the areas that you need help on.
The vast majority of ASVAB test takers will ultimately not enlist in the military. The ASVAB Career Exploration Program claims that only two-and-a-half percent of those who participate in the ASVAB join the military. Forty-seven percent of those who take the exam indicate an interest in attending a four-year college, and 16 percent of those who take the exam originally indicate some kind of an interest in joining the military.
Once you have learned about yourself, you are ready to begin exploring different career options. Chances for a rewarding career are improved if you select a career field that matches your interests, values, skills, and abilities. While learning about various careers, you should be constantly asking yourself, “How well does this career match my current interests, values, and abilities?” and “Will this career lead to a lifestyle I want?”
The Armed Services Vocational Aptitude Battery is more commonly known as the ASVAB Test. If you are interested in a military career, you will need to pass this challenging test in order to qualify. It is used for all branches of the military which includes the Army, Navy, Air Force, Marines, National Guard, and Coast Guard. It is also used to gauge your abilities in specific areas that may be relevant to your job assignments within the military. For more information about the exact details of this exam, check out our article titled What is the ASVAB Test?
Anyone who is planning to enlist in the United States Armed Forces should be familiar with the military’s standards and screening processes. An important part of this screening process is the Armed Forces Qualification Test (AFQT), which is a subsection of the Armed Services Vocational Aptitude Battery (ASVAB). This standardized assessment measures a candidate’s skills in the areas of paragraph comprehension, word knowledge, arithmetic reasoning, and mathematics knowledge.
The Armed Forces Qualification Test (AFQT) covers four sections from the Armed Services Vocational Aptitude Battery (ASVAB): Word Knowledge, Paragraph Comprehension, Arithmetic Reasoning, and Mathematics Knowledge. These four sections and your scores on them make up the Military Entrance Score, also known as the AFQT. Your AFQT score is used to determine your eligibility for entrance into the Armed Services.
As of 2017, the U.S. spends about US$610 billion annually to fund its military forces and Overseas Contingency Operations. Put together, the U.S. constitutes roughly 40 percent of the world's military expenditures. The U.S. Armed Forces has significant capabilities in both defense and power projection due to its large budget, resulting in advanced and powerful technologies which enables a widespread deployment of the force around the world, including around 800 military bases outside the United States. The U.S. Air Force is the world's largest air force, the U.S. Navy is the world's largest navy by tonnage, and the U.S. Navy and the U.S. Marine Corps combined are the world's second largest air arm. In terms of size, the U.S. Coast Guard is the world's 12th largest naval force. 
Battlefield commission: under certain conditions, enlisted personnel who have skills that separate them from their peers can become officers by direct commissioning of a commander so authorized to grant them. This type of commission is rarely granted and is reserved only for the most exceptional enlisted personnel; it is done on an ad hoc basis, typically only in wartime. No direct battlefield commissions have been awarded since the Vietnam War. The Navy and Air Force do not employ this commissioning path.
After World War II, with the onset of the Cold War, the constant technological development of new weapons was institutionalised, as participants engaged in a constant 'arms race' in capability development. This constant state of weapons development continues into the present, and remains a constant drain on national resources, which some[who?] blame on the military-industrial complex.
Command over the U.S. Armed Forces is established in the Constitution. The sole power of command is vested in the President by Article II as Commander-in-Chief. The Constitution presumes the existence of "executive Departments" headed by "principal officers", whose appointment mechanism is provided for in the Appointments Clause. This allowance in the Constitution formed the basis for creation of the Department of Defense in 1947 by the National Security Act. The DoD is headed by the Secretary of Defense, who is a civilian and member of the Cabinet. The Defense Secretary is second in the U.S. Armed Forces chain of command, with the exception of the Coast Guard, which is under the Secretary of Homeland Security, and is just below the President and serves as the principal assistant to the President in all defense-related matters. Together, the President and the Secretary of Defense comprise the National Command Authority, which by law is the ultimate lawful source of military orders.
I have already served in the military years ago. But I wondered if there was a primer that might have helped me improve my test scores. I think this book would help. Unfortunately it's hard to learn enough from a book to do well on the math and reading comprehension of the ASBAB test. Study hard in math and English class in high school. It's hard to cram from a book to pass a comprehensive test that covers many topics. I think it may give you a few extra points, however.