Ezra F. Vogel, a well-known expert on China-US relations and East Asia, died at age 90 on Sunday in a hospital in Cambridge, Massachusetts, in the United States, due to complications from surgery, according to a letter from his family made available to China Daily.

Fairbank Center for Chinese Studies at Harvard University expressed sadness on Twitter over the passing of Vogel, who was the Henry Ford II professor of the social sciences emeritus and former director of the center.

"He was a true champion of our center, an erudite scholar and a wonderful friend. He will be truly missed," the center said.

Foreign Ministry spokesman Wang Wenbin offered deep condolences on Monday over the death of Vogel, saying that he was a renowned US expert on China and an old friend of the Chinese people.

"Professor Vogel made unremitting efforts to promote communication and exchanges between China and the US and enhance mutual understanding between the two peoples. We will remember his contribution to promoting China-US relations," he said.

Cui Tiankai, Chinese ambassador to the US, also said that he had known Vogel for a long time and learned a great deal from him. He sent his deepest condolences to Vogel's family on social media on Monday.

"So sad to learn of the passing of Professor Ezra Vogel," he wrote. "He was an outstanding scholar on China and an old friend of the Chinese people. Throughout his lifetime, he was dedicated to greater mutual understanding between the Chinese and American peoples and made significant contributions to their friendship and China-US relations. His wisdom and insight on China has been of immeasurable value not only to people in the field of study but also to the world."

Vogel grew up in a Jewish immigrant family in the small town of Delaware, Ohio. He was originally trained as a sociologist studying the family in the US. He devoted two years to language study and field research in Japan from 1958 to 1960, emerging as a specialist on Japanese society. The Japanese edition of his book Japan as Number One: Lessons for America (1979) was a bestseller in Japan.

In the 1960s, he embarked on Chinese-language studies, before it was possible for US citizens to travel to the Chinese mainland, and became an accomplished scholar of Chinese society as well.

He served as the National Intelligence Officer for East Asia with the National Intelligence Council from 1993 to 1995, and maintained a strong interest in US foreign and security policy in Asia from that time.

Many Chinese people got to know Vogel because of his work Deng Xiaoping and the Transformation of China (2011). Vogel spent a decade researching and interviewing people after retiring from Harvard in 2000 to complete the monumental work.

But his research on China went far beyond that. Over the past four decades, he conducted research on Sino-US relations and participated in various levels of exchanges between China and the US, witnessing the ups and downs of bilateral relations.

While addressing a video seminar of the Beijing Xiangshan Forum on Dec 1, Vogel said relations between China and the US are at a historical low point, which is not good for either country.

He said that US President-elect Joe Biden would bring new opportunities to Sino-US relations. He also said, instead of denigrating China's constructive efforts around the world, the US should recognize China's contributions to the world and treat China more fairly.

Ezra F. Vogel (1930-2020)