Charles Shaar Murray spent months with John Lee Hooker researching his biography and studying the man's music.
He spoke to BBC News Online about what he found.
Is there a brief way of describing John Lee Hooker's contribution to music?
John Lee Hooker was both an absolutely archetypal product of the blue culture of the Mississippi Delta in the first half of the 20th century - but at the same time, an utterly unique and distinctive performer who it was literally impossible to mistake for anyone else.
How would you define that uniqueness?
John had an astonishing mastery of communicating emotional nuance - with quite a lot of John's records, if you read the lyric written down on a piece of paper it would seem banal or shallow, but once he animated it, once he sang it, it became profound.
Then there's his astonishingly cavalier approach to academic notions of the bar line - John very rarely played a 12-bar blues, it could be 11 or 13 bars, and he didn't go on to the next line of song until he had checked every drop of meaning out of the line before.
And this emotional fearlessness was certainly a massive influence on someone like Van Morrison, for example.
And although they were equally distinctive vocal presences, it was much easier to try to imitate Muddy Waters or Howling Wolf - but John Lee Hooker was utterly inimitable.
Why did this music speak to British blues and rock musicians so much in the 1960s?
I think it's because it contained an emotional truth which was largely missing from the official culture of post-war Britain, which was very buttoned up, very inexpressive.
That generation born during and immediately after WWII, I think had a hunger for some emotional truth and spiritual realism and they found it more in the blues than anywhere else.
This was music made by people who were not afraid of speaking their minds and saying what was in their hearts.
How much is there of Africa in John Lee's music?
There is all of Africa in John Lee's music.
One of my fondest memories was a few years ago - I was in Mali being driven across the Sahara desert the singer and guitarist Ali Farka Toure.
We stopped for a while - at a really small village, too small to be on any map - and Ali put a cassette of John Lee's music into the sound system of his jeep, and turned the volume up.
And practically the whole village came up and started to dance around the jeep. Ali said, "They don't understand the words, but they recognise the music as theirs."
The African-ness of John Lee's music was always something that he himself was very sceptical about.
But it was something that Africans recognized - that John Lee's music might have come by a circuitous route, but its origins were in Africa.
When you spent time with John Lee researching the biography, did you feel you managed to penetrate the carapace of a man who'd spent his life on the road - and get through to the real man?
I think I did. The way to get through to John Lee was not to push - because if John felt under pressure he would either get very irritable or else he would just shut down.
But I spent quite a lot of time with him, and I learnt that if you took things at John Lee's own pace - if you took the time to understand him then moved at his pace - it's like playing music with him, you've got to play in his groove, or your not playing his music.
As in art, in life.
Did anything surprise you about his personality?
He was very warm and gentle soul beneath that slightly forbidding persona.
The private John Lee was a very warm, loving and generous person who really enjoyed his fellow humans, unless it was a specific individual who had harmed or insulted him in some way.
And he loved to laugh.
Playing the Devil's advocate, could it be said his music rather narrow, rather limited?
John's music was indeed narrow in terms of the number of different keys he played in, the number of different tempos he worked in, the harmonic palette.
But the compensation was that its depth was extraordinary. He would regard songs as platforms for improvisation, and would return to his favourite ones many times over - each time attempting to bring something new to them or find something new within them.
As a vocal improviser he was a giant - the only peers I could think of would be the Jamaican singer Winston Rodney, known as Burning Spear, or in pop, Van Morrison.
There has never been anybody like John for communicating complex emotions with only the sound of his voice.
There was never anybody to match him at that and I doubt now there ever will be.
Boogie Man: The Adventures of John Lee Hooker in the American 20th Century, Charles Shaar Murray (Viking/Penguin)