Lawyer who won billions of dollars for clients in asbestos cases and served as finance chairman of John Edwards's presidential campaign. Founder of the Dallas-based Baron & Budd law firm, said he had worked as a youth sweeping mounds of asbestos from a factory floor. He later built his legal career by suing makers and users of the material, including W.R. Grace & Co. and Halliburton Co., over claims that exposure caused lung disease and mesothelioma, a fatal cancer. Baron & Budd also represented clients claiming injuries from drugs and toxic chemicals. Mr. Baron later sold his stake in Baron & Budd to be more active in Democratic politics, lobby against changes to limit lawsuits and serve as campaign finance chairman for Edwards, a former U.S. senator from North Carolina. The New York Times reported in August that Mr. Baron had a role in helping Edwards, who is married, conceal an affair with Rielle Hunter, who produced videos for the presidential hopeful's campaign. He was a 1968 graduate of the University of Texas at Austin and a 1971 graduate of its law school.