Richard H. Solomon, a China scholar who assisted in the historic “Ping-Pong diplomacy” that led to the opening of U.S.-Sino relations in the 1970s, who became an authority on China’s pressure tactics during negotiations and who, as a top American diplomat, helped end a long-running conflict in Cambodia, died March 13 at his home in Bethesda, Maryland. He was 79.

The cause was brain cancer, said his wife, Anne Solomon. He retired in 2012 after 19 years leading the U.S. Institute of Peace, a congressionally funded research group for conflict resolution.

Solomon was an intellectual polymath whose interests encompassed science, photography and international affairs. His career took him from academia to senior positions in government and think tanks.

He joined the Institute of Peace after seven years with the State Department, where as assistant secretary of state for East Asian and Pacific affairs from 1989 to 1992 he represented the United States in peace talks on Cambodia. He also served six months as ambassador to the Philippines.

His State Department portfolio, at various times, included democratization movements from Manila to Santiago, Chile, and nuclear arms talks with Moscow and Pyongyang, North Korea. Secretary of State George Shultz praised Solomon’s skill in strategic long-term planning, particularly on the “evolving relationship” with the collapsing Soviet Union.

But the central focus on his life’s work was China.