The writer and militant Rosa Guy, who has died aged 89 in New York, was best known for her unflinching young-adult fiction. Of a career that spanned decades, she once said: "What I write about in large part is the state of mind of the Harlem community", and: "My concerns are the actual, everyday existence of its people: the hostilities, the anger and the small snatches of happiness."
Her most acclaimed work, A Measure of Time (1983), recreated Harlem life from the 1920s to the 1950s in the tenement flats and ageing thoroughfares that shaped the lives of generations of black people. Maya Angelou said that after reading it, "I [was] so overcome that I fell to weeping."
Rosa Cuthbert was born in Diego Martin, Trinidad, in 1922, and spent her first few years there. Her parents emigrated to the US, where Rosa and her sister, Ameze, joined them after three years spent in the care of relatives. Coming of age in New York in the 1930s was rough. The girls' parents separated and they lived with their mother until her death in 1934, when they rejoined their father. There was little money, and periods were spent in foster care.
However, Rosa did have West Indian kin and working-class roots. She marvelled at tales of the Jamaican Marcus Mosiah Garvey, leader of the world's largest black movement. In her teens, she became a factory worker and shop steward fighting racism in the powerful International Ladies Garment Workers Union (ILGWU).
In 1941 she married Warner Guy, with whom she had a son, but the marriage ended in divorce in 1946. She started to write and her earliest published works were short stories – "Magnify" and "Carnival" – which CLR James published in the 1960s in Trinidad.
Her activism persisted. Her first novel published in America and Britain, Bird at My Window (1966), was dedicated to the memory of Malcolm X, "... the pure gold salvaged from the gutter of the ghetto in which we live." This signalled her beginnings as a prolific writer and a lifetime activist, said Louise Meriwether, a friend of many decades.
Soon Guy's literary activism reflected Harlem's concerns. With her fellow writer John O Killens and the pan-Africanist scholar John Henrik Clarke, she co-founded the Harlem Writers Guild in 1950, the oldest organisation of writers of the African diaspora. Writers from the collective have influenced the movement for black literary liberation and include Angelou, Paule Marshall, Alice Childress and Audre Lorde. Later, as president, Guy explained, "What we wanted was to have a group that really projected the life, the style, the dialogue, the expression that could only come from the black experience in the United States".
For such a gritty subject, her novels for young people are lyrical and radical. Black boys, perhaps like young Malcolm Little (later Malcolm X), came of age amid violence, drugs, corruption and crime. Their troubles crowd her teenage novels, And I Heard a Bird Sing (1987), New Guys Around the Block (1983) and The Ups and Downs of Carl Davis III (1989), among others.
Guy's trilogy The Friends (1973), Ruby (1976) and Edith Jackson (1978) won praise from the American Library Association and attracted an almost cult-like following. Women thanked her for addressing the unspoken, powerful forces of race, sexuality and class that cripple black adolescent girls. She attracted a new following among Afro-Europeans through her lectures at the Institut Fur Jugendbuchforschung in Frankfurt and London's Riverside Studios in the 1980s.
African liberation was in her scope, too. In 1961, Guy and other black militants, including Angelou, Abbey Lincoln and Max Roach, stormed into the UN General Assembly to protest about the assassination of Patrice Lumumba, first prime minister of the Congo. They shouted down the US ambassador, Adlai Stevenson, in an incident never before seen at the United Nations. "That rage became a part of us," Guy recalled, "a rage that went on to become part of the Black Revolution of the 1960s and '70s and the Black Power Movement."
At the time of her death from cancer, Rosa Guy had won international acclaim and numerous prestigious awards: the Coretta Scott King Award, The New York Times Outstanding Book of the Year citation and the Phyllis Wheatley award for contributions to literature. Her son died in 1995, but the five grandchildren who survive her – Didier, Warner, Charles, Alice and Ameze, and a grandnephew – called Guy "Mama Rosa"; to her six great grandchildren she was "GGMA", great grandma.
Rosa Cuthbert, writer and activist: born Diego Martin, Trinidad 1 September 1922; married 1941 Walter Guy (divorced 1946; one son deceased); died New York 3 June 2012.