Cao Tingdong · Laolao Hengyan

Cao Tingdong's Laolao Hengyan (1773) — the only text in this library written by an old man, for old people, completed at the age of eighty-four. Guided by the principle that the Way values what is natural, it centers on stillness, care of digestion, and the doctrine that in old age it is better to take too little medicine than too much. It substitutes walking for elaborate gymnastics on fall-risk grounds, revises the older doctrine that too much sleep stagnates qi, and devotes two full volumes to clothing, footwear, canes, beds and bedding — treating everyday objects as health technology. Its final volume grades one hundred congees into three ranks. Eight modules — bilingual (Chinese lectures + English teaching), with Chinese MP3 narration. (Wellness-focused; classical dietary and medicinal material is historical education, not health advice, and no dosages are given.)