The attempt to prevent Mr. Wong from participating in the event has highlighted concerns about free speech in Hong Kong, a semiautonomous Chinese territory that was promised it could maintain its own political, economic and legal systems after the 1997 handover from Britain. The episode has also renewed questions about the influence that China, and people with deep business interests in China, hold over universities, nongovernmental organizations and other groups that rely on wealthy donors.

“I have watched with alarm over the past decade the increasing force field that has been projected by China on think tanks, universities, civil society organizations and cultural groups,” said Orville Schell, director of the Center on U.S.-China Relations at the Asia Society. “The reality is that if you want to work with China, you have to be discreet. I would say it’s a worrisome trend.”

Mr. Wong was a leader of the 2014 Umbrella Movement, which takes its name from the umbrellas protesters used to defend themselves from police pepper spray during a monthslong occupation of major roadways in Hong Kong. The demonstrators were calling for a more direct say in the election of Hong Kong’s chief executive, the top political office. China’s central government had proposed direct elections, but only of candidates who had been vetted by a largely pro-Beijing nominating committee, a limitation that the protesters and pro-democracy lawmakers rejected.

The book event last month was moved to the Foreign Correspondents’ Club. Mr. Wong ended up not attending, as he was participating in a protest where he was arrested.

In the fall, the Hong Kong Center of the Asia Society canceled a screening of a documentary on the Umbrella Movement because of concerns that a panel on the film would have only included pro-democracy viewpoints.