The English folkie left behind three perfect records when he died of an overdose in 1974. It took a recent Volkswagen commercial for them to find an audience.
Posthumous fame is nothing new to pop music, but it's usually immediately posthumous.
His life's work is finite, small and, with a single exception, perfect. There is no ramp-up or decline. He didn't live to build his early work's reputation through touring and recording and headline making, the way that Lou Reed did with the Velvet Underground or Iggy Pop did with the Stooges. He said his piece, and then he took too much Tryptizol and died. Anyone could have told you that from listening to his records, and beyond that there was no real substance to the book.