'If people know my work, it's as a 'movie guy',' says the Edinburgh-based filmmaker and film historian Mark Cousins, who has broadened his approach to visual culture significantly with the publication of his book – discussed this month at the Edinburgh Festival - The Story of Looking. 'My first love was science, though. My hobby is travelling to see buildings and I studied art history, so The Story of Looking was a way of writing about some of my other passions.'

'Over the years I came to realise that looking is the theme of a lot of my films, and that looking keeps me happy. When I'm feeling down I go people watching, I look across the Firth of Forth, I go to see cities, and this cheers me up. At the same time, looking technologies like cameraphones, skype, virtual reality and so on have been transforming our visual lives, so I thought that the time was right to tell the story of those lives.'

The book itself is weighty and comprehensive, full of the depth of analysis that fans of Cousins' expect from his reading of films. 'The actual writing of it was about eight months, every day and long hours,' he says. 'The research took a bit longer, as I had to inform myself about the science of looking in sport, for example, or the visual culture of the Crusades and slavery. I had lots of gaps to fill. The full jigsaw was completed over a few years, and as a result of the research I changed my sense of what looking is. I came to notice, for example, that the best lookers were often – like Copernicus, who was in Poland -– outside the centres of power, or had childhood infirmities which meant that they were on the sidelines of life, watching things unfold.'

With his next film project slated to be a 16-hour documentary series entitled Women Make Film, the book is less immediate than Cousins' films, but he's content with the fact it's out there and telling a unique story. 'It would have been nice if it had taken off like a firework in the sky, but it's been a slower burn than that,' he says. 'Hopefully it's quite a rich read – it's not something you whizz through in a day – and I'm delighted that it's coming out in many other countries like China, Russia, Spain, Italy and America itself. The story I tell is a properly international one.'

Spark Theatre on George Street, 0345 373 5888, 24 Aug, 8.45pm, £12 (£10).