Retired last year from the position as senior government affairs desk manager for the medical equipment industry at the European Union Chamber of Commerce in China, Mueller's career has been intertwined with China's rapid economic and technological development over the past four decades.
This has resulted in him feeling an obligation to act as a bridge between people from China and Germany and clear up misunderstandings his countrymen have toward China. He is writing down his experiences and his witness of the changes brought by reform and opening-up.
He's also been writing an introduction to the history, preservation and revitalization of the Central Axis of Beijing, a city he's settled in for more than two decades, and he's also translating Chinese literature into German.
Mueller says he has discovered in China diverse cuisines and landscapes, as well as people's solidarity and spirit of helping each other in dealing with life's challenges.
He recognizes one major difference in the way of thinking between the Chinese and Germans. In facing new technologies, the Chinese prioritize opportunities, while his countrymen are more prudent about potential risks.
Despite more and more Chinese being able to speak other languages, Mueller still encourages foreign managers working in China to learn Chinese, particularly because speaking the language brings them closer to those they employ, as well as to customers and government officials, and helps improve work efficiency, enhance trust, and makes life here richer.
He also suggests that Chinese people learn more languages, such as his mother tongue.
Without learning Chinese, foreigners risk isolating themselves from Chinese culture and it will be difficult for them to gain insight into the technological and social development that China is willing to share with the world, Mueller says.
He expresses the hope that more German schools will teach Chinese as a foreign language.
