What makes a good book?

I've just finished reading The Time Traveller's Wife by Audrey Niffenegger. It's probably the best novel I've read in a long time, and I can't believe I've only just discovered it. Poignant, beautifully written and structured, I didn't want to put it down, and at the same time, I wanted to prolong the experience of reading it.

This has led me think about the experience of reading. What makes a good book? What do we mean by 'good'? It is a complex question that I can't easily answer.

There have been novels I have breathlessly rushed through in order to find out what happened, so caught up in the intensity of the story that I felt I had little choice but to read on. Some of these were little more than compelling froth, but that didn't mean I didn't enjoy them at the time. Other novels I have read more slowly, content to pick them up and put them down, reading a little at a time and savouring the prose like a fine wine. Then there are old favourites, books that I will return to time and time again, old friends I am delighted to visit (Lord of the Rings and anything by Jane Austen come into this category).

It is amazing how some books, particularly those we have loved and read over and over as children affect us. One of my most vivid memories from my childhood is of reading The Chronicles of Narnia. It was just before my seventh birthday. The magic of that time has never left me. For at least a couple of years afterwards, I continued on my quest to find Narnia whenever we visited my grandmother's house. As a child, her house seemed huge, and there were several wardrobes filled with fur coats. I remember thinking that if I kept trying, sooner or later, I would get there.

Although I never reached Narnia, it did not stop me trying. However, before long, I discovered I could create my own worlds, vast countries that I could access any time I liked. I'm still doing it now.