黄帝内经
The first text, the "Suwen" (), also known as "Basic Questions", covers the theoretical foundation of Chinese Medicine and its diagnostic methods. The second and generally less referred-to text, the "Lingshu" (; "Spiritual Pivot"), discusses acupuncture therapy in great detail. Collectively, these two texts are known as the "Neijing" or "Huangdi Neijing." In practice, however, the title "Neijing" often refers only to the more influential "Suwen".