Charles M. Walker, 85, a Los Angeles tax attorney who worked in the U.S. Treasury Department. Born in St. Louis, Walker earned his undergraduate and law degrees from the University of Missouri and served in the Army during World War II. He established his law practice in Los Angeles with Brady, Nossaman & Walker, and in 1962 became a name partner in the firm Paul, Hastings, Janofsky & Walker. In 1975, he left the law firm for two years to accept an appointment from President Gerald R. Ford as assistant secretary of the Treasury for tax policy. After his retirement in 1981, Walker served six years as a director and trustee and, for a year, president of the American Bar Retirement Assn., which administers retirement plans for lawyers. From 1988 to 1994, he was a regent of the American College of Tax Counsel, and helped establish its nonpartisan American Tax Policy Institute to analyze tax issues. He served on the institute's board for six years and was president for three. On Saturday in Los Angeles of heart failure.