In what year was the NCO Manual established?

The NCO Manual was established in 1917, marking a significant development in the professionalization and training of non-commissioned officers in the military. This year was notable, as it was during World War I, a time when the need for structured training and guidance for enlisted leaders became crucial in the face of increased military operations and complexities. The establishment of the manual represented an effort to standardize the training and responsibilities of non-commissioned officers, thereby enhancing their effectiveness and ensuring a more cohesive military structure. Such foundational documents play a vital role in shaping leadership within the armed forces and have lasting impacts on military culture and training practices. The other years provided in the options relate to various developments in military doctrine but do not represent the establishment of the NCO Manual, making the year 1917 the correct choice for this question.