Mr. Mosser, 50, was killed Dec. 10 by a bomb that was mailed to his North Caldwell, N.J., home (see stories on Page 3).
"He was the closest thing to a Boy Scout you're going to find in business today, in a world focused on abstract goals and self-aggrandizement," said James Dowling, former CEO of Burson-Marsteller, the Y&R public relations unit where Mr. Mosser spent most of his career.
After graduating from St. Bonaventure University with a degree in journalism, Mr. Mosser worked briefly for The Associated Press before joining the U.S. Navy in 1965.
As a naval officer, he served four years in Vietnam before taking an account-management post at Burson's New York office in 1969.
In a 25-year career at one of the nation's pre-eminent PR operations, Mr. Mosser moved up to general manager of the New York office in 1983, president of its U.S. operations in 1987 and president of its Americas division in 1989.
Along the way, he helped manage AT&T's torch relay during the 1984 Summer Olympics. He also managed crises both large and small, ranging from the 1982 Tylenol poisonings to Philip Morris Cos.' thorny corporate issues to the ill-fated introduction of new Coke.
Most recently at Burson, he was vice chairman and chief operating officer, and completed a year's tour in the agency's London office before returning stateside and moving over to Y&R in January as exec VP.
Just nine days before his death, Mr. Mosser was named general manager of Y&R Inc., responsible for coordinating the company's vast array of resources as Y&R struggled to meet clients' changing needs with "problem solvers, not just tactical specialists," Peter Georgescu, Y&R's chairman-CEO, said in announcing the promotion.
"He was a great guy," Mr. Georgescu said last week. "He had a great wit and he was a terrific human being."