He began to write only with collaborators who were willing to finish what he started. ''He had great ideas, but no follow-through,'' said Mr. Passell, who worked with him on articles for the New York Review of Books, The New York Times and on three books about economics, relations between the Federal Government and the states, and a popular compendium of the best in everything from pizzas to police precincts called ''The Best.''

At Columbia, Benno Schmidt recalled, Mr. Ross ''was not a particularly successful teacher.''

''His mind moved so fast,'' Mr. Schmidt said, ''he tended to skip over the intermediate premises somewhat without articulating them. The students found him a little bewildering, and that bothered him a lot.''

When Mr. Ross was not teaching, he was working as a researcher in David Garth's political consulting firm, doing position papers for John V. Lindsay's 1972 Presidential race. He liked the camaraderie - and collaboration - of politics, and talked about running for office himself someday.

''He didn't want to be Merlin or a court jester or a talking head,'' said Mr. Popkin. ''He wanted to be a man of action.'' A Frustrating Time In Government Service In 1973, Mr. Ross resigned from Columbia and went to California to work on the gubernatorial campaign of Jerry Brown, who had been at Yale with him.

With scissors, stapler and yellow pad, Mr. Ross became the issues and ideas staff for the future governor. He helped put together Mr. Brown's first budget and was rewarded with a six-year appointment to the Public Utilities Commission. He quit after two years.

Mr. Ross took a job with the State Department under Jimmy Carter, working for a former teacher at Yale, Richard Cooper, who was an under secretary for economic affairs. There, he believed, he would be able to influence national events.

''He was unhappy when he came to Washington and realized that Dick Cooper, and even Jimmy Carter, had as many constraints on them as Lenny had had in California,'' said Mr. Levine, who was in Washington himself during that period working as the general counsel for the Civil Aeronautics Board. ''He became aware in a very direct way that this wasn't a world in which you just got to the right place and then got to the levers and really changed things.''