Gerald Nagler, a prominent human rights activist who made risky Cold War forays into the Soviet Union and Eastern Europe to lend support to dissidents including Nobel laureate Andrei Sakharov and future Czech President Vaclav Havel, died at his home in Stockholm.

His death was announced by the Stockholm-based Civil Rights Defenders, the successor to the Swedish Helsinki Committee for Human Rights, which Mr. Nagler founded in 1982.