He was known for his extensive contributions to the study of the history and archaeology of Karnataka, particularly the Vijayanagara Empire.
Here are some of his notable works:
* The History of the Vijayanagara Empire: This is considered one of his most important works, providing a comprehensive account of the empire's rise, reign, and fall.
* Indian Archaeology
* The Rise and Fall of the Vijayanagara Empire
* Studies in the History of the Vijayanagara Empire
* Karnataka: A Land of Great Kings
* The Archaeology of Karnataka
* Ancient Indian History
C. Hayavadana Rao's writings were highly influential in shaping our understanding of the Vijayanagara Empire and the history of Karnataka. He combined meticulous research with a clear and engaging writing style, making his works accessible to both scholars and general readers.