BBC Music: The general perception of Kurt Cobain is someone who was immensely talented but complex, dark and, in many ways, an unwilling participant of Nirvana's success. But you paint another picture, of a person who was much more in control and calculating about the band's image and success.

Goldberg: Oh, he was the architect of Nirvana's success. He made every single decision. He wrote all the songs, all the famous songs, anyway, the lyrics and the music. He made the final decisions about every mix, about the mastering. He designed the album covers. He was the lead singer and the lead guitar player. He did most of the interviews. He storyboarded the videos. He designed the T-shirts, and he paid attention 24/7 to this career that he had imagined when he was younger, and that he executed in an extremely sophisticated level. There were aspects of the results of success that he didn’t like. He certainly detested the media interest in his personal life, and he wasn't crazy about being recognised if he went to the store or something like that. But he created it. It didn’t happen by accident.

BBC Music: Were there any sort of decisions that he was making in the artistic sphere that he felt he lost control of, or regretted in retrospect, after the band were successful?

Goldberg: I don't think he regretted any artistic decisions, not that I'm aware of. I think he was a big Kurt Cobain fan. This is a guy who put together an anthology of his early songs when he was 24 years old, after Nevermind came out, and released Incesticide just to make sure his full body of work was documented and curated the way he wanted it. There were certain shows that he wasn't happy with. He was self-critical in that respect, but I think he was quite happy with the records and the videos, because he worked so hard on them, and he thought about them so much, they were the result of what he wanted.

I think that there were aspects of being successful that didn’t feel the way Kurt expected it to feel. A part of it was that he had a lot of inner pain. He had a terrible childhood, prone to depression, and had done heroin long before he became famous. Being successful didn’t make all that pain go away. It gave him the satisfaction of being successful and expressing himself, but he still had these demons. That was like the shock of, you know, you get what you want, but it still doesn't solve all of your inner problems.