Question: Who wrote the introduction to the book Cleaver wrote in 1968?

full_context: Document 1: The Motion of Light in Water: The Motion of Light in Water: Sex and Science Fiction Writing in the East Village is an autobiography by science fiction author Samuel R. Delany in which he recounts his experiences as growing up a gay African American, as well as some of his time in an interracial and open marriage with Marilyn Hacker. It describes encounters with Albert Einstein, Bob Dylan, and Stokely Carmichael, a dinner with W. H. Auden, and a phone call to James Baldwin. Hazel Carby called it one of two contemporary autobiographies that are "absolutely central to any consideration of black manhood" (the other being that of Miles Davis). Among many cultural events of the decade that he witnessed, Delany recounts his attendance at the first New York City performance of artist Allan Kaprow's "18 Happenings in 6 Parts", the 1959 performance piece that, for many, marks the end of modernism and the beginning of postmodernism. In section 17.4 of the University of Minnesota Press edition, he describes the event and its venue, and speculates on its artistic significance. The introduction puts an emphasis on the idea of the unreliable narrator; Delany's accounts often contrast his life as it "felt" to ways in which it actually occurred. In the chapter, The Future Is in the Present of the book "Cruising Utopia" by José Esteban Munoz, Delany's The Motion of Light in the Water serves to explain how the future, as a formed of utopia, can be "glimpsed" in the present through what Delany employed as "the massed bodies" of sexual dissidence.
Document 2: Soul on Ice (album): Soul On Ice is the critically acclaimed debut album by West Coast emcee Ras Kass, released on October 1, 1996, under Priority Records. The album was produced by Ras Kass, as well as DJ Battlecat, Vooodu, Bird, Michael Barber, Michael Schlesinger, and Reno Delajuan. Fellow West Coast rapper Coolio makes the only guest appearance on the album on the song "Drama." The album's title is a reference to Black Panther member Eldridge Cleaver's 1968 book "Soul On Ice".
Document 3: Maxwell Geismar: Maxwell Geismar (August 1, 1909 – July 1979) was an American author who wrote the introduction to Eldridge Cleaver's "Soul on Ice". He signed the Triple Revolution statement sent to President Lyndon Johnson in 1964.
Document 4: Eldridge Cleaver, Black Panther: Eldridge Cleaver, Black Panther is an Algerian documentary film made in 1969, in which Black Panther activist Eldridge Cleaver speaks from exile in Algeria, where he had moved after the state of California tried to charge him with intent to murder. In the documentary, Cleaver discusses revolution in the United States and speaks against such political enemies as Richard Nixon, Spiro Agnew, Ronald Reagan and Richard J. Daley.
Document 5: Max Morise: Max Morise (1900-1973) was a French artist, writer & actor, associated with the Surrealist movement in Paris from 1924 to 1929. He was friends with Robert Desnos and Roger Vitrac before they joined the Surrealist movement. He contributed articles to "La Revolution Surrealiste" and took part in a series of round table discussions held by the group, regarding the nature of sex. He also participated in several Surrealist games, most famously the "exquisite corpse". André Breton quotes Morise twice in the first "Surrealist Manifesto"; after saying "We do not have any talent", Breton provides a quote by Vitrac and Paul Éluard, then says "Ask Max Morise" and provides this quote:
Document 6: Soul On Ice (book): Soul On Ice is a memoir and collection of essays by Eldridge Cleaver. Originally written in Folsom State Prison in 1965, and published three years later in 1968, it is Cleaver's best known writing and remains a seminal work in African-American literature. The treatises were first printed in the nationally-circulated monthly "Ramparts" and became widely read (even praised by Norman Mailer) for their illustration and commentary on "Black America". Throughout his narrative, Cleaver describes not only his transformation from a marijuana dealer and serial rapist into a convinced Malcolm X adherent and Marxist revolutionary, but also his analogous relationship to the politics of America.
Document 7: In the Spirit of Crazy Horse: In the Spirit of Crazy Horse is a book by Peter Matthiessen which chronicles "The story of Leonard Peltier and the FBI's war on the American Indian Movement". It was first published in 1983. Leonard Peltier was convicted of murder in 1977 and sentenced to life in prison for the 1975 killing of two FBI agents, after a trial which the author alleges was based on widespread fraud and government misconduct. The book portrays the violent turmoil on the Pine Ridge Indian Reservation during that time, including the 1973 'Wounded Knee Incident' and the following "reign of terror", and describes the 1975 'Pine Ridge Shoot–out' or 'Oglala Firefight' and the subsequent trials and their aftermath. Distribution of the book was interrupted for almost a decade while legal challenges against it were resolved.
Document 8: Max Manus: Maximo Guillermo "Max" Manus DSO, MC & Bar (9 December 1914 – 20 September 1996) was a Norwegian resistance fighter during World War II, specializing in sabotage in occupied Norway. After the war he wrote several books about his adventures and started the successful office supply company "Max Manus AS".
Document 9: Max Kruse (author): Max Kruse (November 19, 1921 – September 4, 2015) was a German writer, mostly known for his children's books "Der Löwe ist los" (The Lion is on the loose) and "Urmel aus dem Eis" (Urmel from the Ice Age).
Document 10: John C. Maxwell: John Calvin Maxwell (born 1947) is an American author, speaker, and pastor who has written many books, primarily focusing on leadership. Titles include "The 21 Irrefutable Laws of Leadership" and "The 21 Indispensable Qualities of a Leader". His books have sold millions of copies, with some on the New York Times Best Seller List.
Document 11: Iceberg Slim: Robert Beck (born Robert Lee Maupin or Robert Moppins, Jr.; August 4, 1918 – April 28, 1992), better known as Iceberg Slim, was an American pimp who subsequently became an influential author among a primarily African-American readership. Beck's novels were adapted into movies, and the imagery and tone of Beck's fiction have been acknowledged as an influence by several rap musicians, including Ice T and Ice Cube, whose names are homages to Beck.
Document 12: Max Ehrmann: Max Ehrmann (September 26, 1872 – September 9, 1945) was an American writer, poet, and attorney from Terre Haute, Indiana, widely known for his 1927 prose poem "Desiderata" (Latin: "things desired"). He often wrote on spiritual themes.
Document 13: Max Elbaum: Max Elbaum is an American historian, author, and social activist. He has written extensively about the New Left, Civil Rights Movement and anti-war movement. His book on the "new communist movement" of the 1970s and 1980s, "Revolution In The Air: Sixties Radicals turn to Lenin, Mao and Che", was praised by Pulitzer Prize-winning historian David Garrow as "an absolutely first-rate work of political scholarship".
Document 14: Eldridge Cleaver: Leroy Eldridge Cleaver (August 31, 1935 – May 1, 1998) was an American writer and political activist who became an early leader of the Black Panther Party. His 1968 book, "Soul On Ice", is a collection of essays that, at the time of its publication, was praised by "The New York Times Book Review" as "brilliant and revealing". In the most controversial part of the book, Cleaver acknowledges committing many acts of rape.
Document 15: George Jackson (activist): George Lester Jackson (September 23, 1941 – August 21, 1971) was an African-American activist and author. While serving a sentence for armed robbery in 1961, Jackson became involved in revolutionary activity and co-founded the Maoist-Marxist Black Guerrilla Family. In 1970, he was charged, along with two other Soledad Brothers, with the murder of prison guard John Vincent Mills in the aftermath of a prison fight. The same year, he published "Soledad Brother: The Prison Letters of George Jackson", a combination of autobiography and manifesto addressed to a black American audience. The book would become a best-seller and earn Jackson personal fame. In 1971, Jackson took several guards and two inmates hostage in a bid to escape from San Quentin Prison. However, the incident ended with Jackson being shot and killed by a guard, in addition to the deaths of 5 hostages.
ground_truth: Maxwell Geismar