In 1977 Ngugi wa Thiong'o was imprisoned by the government of Daniel Arap Moi following the publication of his novel Petals Of Blood and the production of a play openly critical of the Kenyan authorities.

A decade earlier, Ngugi marked his conversion to a form of anti-colonial Marxism inspired by Frantz Fanon in another novel, A Grain Of Wheat. Another 10 years before that, the point at which this memoir is set, he was a pupil at the prestigious, British-run Alliance school near his home in Kamirithu.

However, there was to be no normal end-of-term homecoming, for in his absence his village was razed and relocated behind high palisades and spiked moats, as defence against local fraternisation with the Mau Mau. Ngugi's brother Good Wallace was with the insurgents in the hills. His mother was tortured at Kamirithu. Ngugi had not taken the blood oath and been given a certificate of political cleanliness. Moved by a Billy Graham film, he accepted Jesus as his personal saviour, a commitment he was later to renounce along with the name James Ngugi.

One might say that Mau Mau and evangelism were the two arms of the cross on which Kenya was being crucified in 1957. It was an extraordinary period. Offstage – as far as Ngugi's narrative here is concerned – Britain was going through a crisis of identity, torn between European and Atlanticist loyalties and twice-torn after Suez; half-fearful of submerging sovereignty in the Common Market, half-excited by the possibility of once again leading Europe as its oldest democracy; committed to the Commonwealth, shackled to the Commonwealth. Nothing better captures the ambivalence of the moment than the enigmatic person of Ngugi's headmaster Carey Francis, a ramrod colonialist deeply critical of the Crown's behaviour in the old Empire, a man of petty prejudices and deep-running convictions.

The contradictions Ngugi explores in this new volume of memoirs (which follows and intersects with Dreams In A Time Of War) might be summed up in flora: petals of blood versus daffodils. The reality of colonialism isn't most forcefully expressed in the "concentration villages" or in the "benign" apartheid of British rule, or even in the demonisation of Mau Mau, but rather in the sense of profound dislocation Ngugi feels, imbibing a culture which takes Europe, even England, as the measure of all things.

How can he quite understand the English devotion to daffodils (Shakespeare, Wordsworth) and the fresh change of seasons, when a Kenyan child is surrounded by green life and flowers all year round? What does he take from a school production of As You Like It, with African boys in 16th-century costumes playing men and women and pretending to be in a wood in France? The experience ultimately led him to develop a new form of participatory theatre for Africans, which ultimately led him to jail.

Ngugi's whole career has been the dramatisation of a highly specific language problem. He first began writing seriously (in English) while studying as a postgraduate in Leeds. He later began to write in his native Gikuyu and in the hybrid Swahili. His great novel Wizard Of The Crow, published after a long exile in the US and a 20-year gap in fiction writing, was made in Gikuyu first and then rewritten in an English version.

Ngugi and his family had returned to Kenya briefly when the original version came out, but he was beaten and his wife raped, ostensibly by thieves. Two years later, he was thrown out of a smart San Francisco hotel. There's no obvious parity in these events but, hinged by a mind framed at a British school in Kenya, they painfully represent a life continuously displaced and brutalised in which the dust that fills the air in The Interpreter's House cannot simply be damped down with the sweet water of gospel, any gospel.

What language best captures all this? It would seem that the only answer is language itself, patient narrative in multiple tongues. No writer alive today has more complex experience to draw upon or greater resource to convey it.