From http://www.dw.de/doris-lessings-legacy/a-17233237

Following the breakdown of her second marriage, [Doris] Lessing left her two eldest children from her first marriage in the care of their father and his second wife and moved to England, taking her son Peter, a large collection of books, and the manuscript for her first novel, "The Grass is Singing." She would spend the rest of her life confronted with questions about her decision to leave John and Jean in Africa.

Citations

1. A Conversation with Doris Lessing (1966). Florence Howe. Contemporary Literature. Vol. 14, No. 4, Special Number on Doris Lessing (Autumn, 1973), pp. 418-436 Published by: University of Wisconsin Press Article Stable URL: http://www.jstor.org/stable/1207464
2. Doris Lessing: her last Telegraph interview 1988. "'They sell a lot of dynamite, Doris,' Peter says. He has shuffled in to say hello, wearing a tea cosy on his head. He lives here, debilitated by diabetes. They had been returning from the hospital on that day of the Nobel announcement. 'This is my son,' Doris says, unnecessarily. 'The other one being dead.' Peter adds, equally unnecessarily. (Her elder son, John, a coffee farmer in Zimbabwe, died of a heart attack in 1992.)"