Prof Gordon B. Downer (1926-98) of School of Oriental and African Studies was a leader in linguistic studies, a specialist in many Sinic languages with a particular interest in the Miao-Yao (Hmong-Mien) languages of the Thai-Burma-Laos-Yunnan borderlands. These papers by Downer are republished as part of the ongoing Thai-Yunnan project of ANU, Canberra.