Moon Tiger by Penelope Lively

I feel now as though someone else wrote it. Which is of course the case – I am not the person that I was 23 years ago. But I remember her, and I know what she was up to, what I was trying to do. I had always wanted to write about Egypt during the second world war, to make use of my own childhood experience there. At the same time. I was interested in the operation of memory, and the nature of evidence, and wanted to weave these preoccupations into a piece of fiction.

What is memory? A crutch on which we lean, or an albatross round the neck? History is a matter of conflicting evidence, and so is private life – my version of a particular event will not be the same as yours. And out of this confusion of concerns, Moon Tiger somehow arose.

I never got my hands on a Matilda tank; I needed to study one, to sit in it if possible. I was going to stick my neck out and write a section from the point of view of my young tank officer, Tom Southern – he commanded a Matilda. The Imperial War Museum did not have one, in 1986; years later, I discovered that there was one at the Tank Museum on Salisbury Plain. But in every other area the Imperial War Museum did me proud: I spent hours in a projection room there watching mute, unedited film of the Libyan campaign – this is the film taken by the official cameramen attached to each battalion which served as the basis for the Pathé Pictorial and Movietone propaganda pieces of the day. This resource, along with the immense archive of still photographs, enabled me to get some idea of the Libyan campaign, and to see it as Tom saw it, and as my narrator, Claudia, saw it on her own foray to the front as a war correspondent. And I read everything I could get hold of – war diaries, the accounts of war correspondents and the few novels that came out of that war. And there was Keith Douglas, of course, the 24-year-old poet who would later die in Normandy.

Research shouldn't show, in a novel; it should serve as the seven-eighths of the iceberg – invisible, but without which the whole thing would capsize. I hope mine doesn't – the labours of that alter ego. And I had another, crucial, background resource, which was my own memory of Cairo in the 1940s. I was born in Egypt, and didn't leave it until I was 12, in 1945. So in my head was the city of that time, overrun with foreign troops, uniforms and battledress all mixed up with the cosmopolitan, polyglot population. The sound and the smell of it – the rattle of trams, clop of horses pulling the gharries that served as taxis, the pervasive whiffs of kerosene, dust and dung. The endless convoys of lorries, armoured cars, jeeps on the desert roads; the Eighth Army buccaneers downing gin and tonic on the terrace of Gezira Sporting Club. I didn't need research; I had it all. A Moon Tiger – that green coil of insecticide – burned beside my bed when I was a child.

After the novel won the Booker, in 1987, I had to talk about it all too much. I was always being asked if Claudia was a reflection of myself. No. I wish. She is much feistier than I am, much more combative. I would rather like to be a Claudia. But I did give her some of my interests, some thoughts about history; we have read the same books, been intrigued by the same figures, the same climactic moments. I suppose there is a sense in which the book is also about the nature of history – what it is, fact or interpretation, evidence or fable. Moon Tiger is a short novel, but – rereading after so long – I'm surprised at its range. And it is impossible to find at once the passage you're looking for, which is almost deliberate, an effect of Claudia's – and my – rejection of the notion of linear memory. In our heads, everything happens at once; the past is a whole lot of slides, any one of which may surface at any moment, some of which are buried, others waiting to surge forth and surprise.

I wrote Moon Tiger in a burst of mid-life energy. Mid-life is a great time for writers; you have the drive, you know something about the craft, you have learned how to home in on an idea and let it develop. I was trying to investigate such concerns in that novel, and tell a story in the process.

Next week John Mullan will look at readers' responses.