The songs on Bowie’s inspired new album speak of illness, death and heaven – and offer intriguing insights about the man who sang, ‘I’m not a pop star, I’m a blackstar’. What the critics didn’t know, however, was that the man behind it had been diagnosed with cancer 18 months ago, and that he knew his life was coming to an end. If this had been common knowledge, they would all no doubt have looked at Blackstar in a different light. Was David Bowie saying goodbye on it? And does it seem obvious now that he has died?