I once worked in this command.
It was challenging and provocative and serious work. New and old military minds alike need efficient, cohesive and standardized training in Strategic and Tactical and Logistical doctrine and the Military Arts. It
was found in TRADOC. It
was delivered to them by the instructors-trainers, researchers and developers and evaluators found within the command. Without them... the force had no better body of SME (subject matter experts) upon which they could depend to put their skills to a purposeful, honorable and dedicated manner.
The author's presentation here is concise and accurate and an excellent overview of the creation of the Training and Doctrine Command of the US Army.