By the age of 18 he had travelled more than 4,000 miles, crossing eight African borders without a passport - a lone boy living on his wits and depending on the kindness of strangers.

Now Aher Arop Bol sells sweets and cigarettes under a railway bridge in the South African capital, Pretoria, but his adventure is not over. He has just become one of the most extraordinary authors in the history of African literature.

Arop Bol has shared his story in a unique memoir, The Lost Boy (published by Kwela Books), which offers a rare insight into the life of a child on the run from war. South Africa, which in May last year was the scene of more than 100 xenophobic killings directed at refugees such as Arop Bol, has greeted his story with fascination. Drum magazine called it an "extraordinary tale of pain, desperation and, above all, survival against all odds". The respected poet and journalist Antjie Krog said simply: "This story stays with me."