publicly broke with Nathaniel and Barbara Branden. She accused Nathaniel Branden of a "gradual departure from the principles of Objectivism", financial exploitation of her related to business loans, and "deliberate deception of several persons". In a response sent to the mailing list of The Objectivist in 1968, the Brandens denied many of Rand's charges against them. The result of their conflicting claims was a "schism", as some participants in the Objectivist movement supported the Brandens, while others supported Rand's repudiation of them. NBI was closed and its offices vacated, in an environment that Barbara Branden described as "total hysteria" as its former students learned about the matter. The Brandens continued for a time to sell some of NBI's recorded lectures through a new company, but otherwise had little involvement with the Objectivist movement until their biographical books about Rand were released. The Objectivist continued publishing with Rand as editor and Leonard Peikoff as associate editor. Peikoff also took over Nathaniel Branden's role as the primary lecturer on Objectivism. Peikoff later described the Brandens' expulsion as the first "of the many schisms that have plagued the Objectivist movement". 1970s In the 1970s, Rand gave fewer public speeches. She concentrated instead on nonfiction writing and on helping the work of her students and associates, through efforts such as a series of private workshops on epistemology that she conducted from 1969 through 1971 for about a dozen students and professionals in philosophy, math and physics. The Objectivist was replaced by The Ayn Rand Letter in 1971. While The Objectivist had published articles by many authors, The Ayn Rand Letter, marketed as a personal newsletter from Rand, published only her work (plus occasionally Leonard Peikoff's). Throughout the decade, Peikoff continued to offer a number of lecture series on various topics related to Objectivism to large audiences, often incorporating new philosophic material. Rand worked closely with Peikoff, helping edit his book, The Ominous Parallels, for which she wrote the introduction. In mid-1979, Peter Schwartz began editing and publishing The Intellectual Activist, a publication which Rand recommended to her audience. One of Rand's associates, philosopher Harry Binswanger, pitched to Rand his idea for a mini-encyclopedia of Objectivism, The Ayn Rand Lexicon: Objectivism from A to Z (1986), and she approved of the project after seeing a sample of the proposed selections. Rand advised him on standards of inclusion but died before the work was completed. After