The blurb on the back tells us this is the seminal book on the subject of creativity. However, you need to understand one very important thing: this book is not about how to be more creative, it's about freeing your creativity. This implies that your creativity has been blocked, which in turn implies that something has gone wrong which should be put right. Julia Cameron tells you the causes of the block, and the Artist's Way is a course of therapy to help you recover. (In each chapter you Recover a Sense of something, eg Compassion, Possibility).
I think the Artist's Way was developed for women of her generation who as children were discouraged from being creative and as adults expected to always put others' needs first. Such experiences mean that a) one doesn't believe in one's own creative abilities, and b) one doesn't have time or space to be oneself. If this is true for you, you may find the Artist's Way very useful.
It is divided into 12 units, one for each week. Although there is a different theme for each week, they didn't seem particularly differentiated to me. Each unit contains a couple of essays on living a better life, as well as some tasks to do; many of them seem to consist of making lists of what you would do/be/buy if you the had time/permission/money. You are also instructed to write 3 pages every morning on whatever is on your mind, and do something enjoyable by yourself as a "date" with your "artist child" every week. Although she says you don't need any religious belief to follow the course, she does talk a lot about spirituality. It has a New Age feel and I think I gave up at the point where I was expected to build an artist's altar and listen to recordings of myself reading aloud my favourite sermons from her book!
Overall, I was disappointed with this book and don't think it did anything to make me more creative. Some of what she writes is interesting, and I liked doing the morning pages - in fact I still do them. However, for me, developing creativity has really been a case of getting into the habit of painting, drawing and taking photographs regularly. I don't find it particularly helpful to blame other people for discouraging me, or to fragment my life into ever more activities and self-indulgences in order to discover my creative self.
If you are thinking of doing the Artist's Way I would recommend you read several units first to see if what she says is true for you. I didn't, and stuck with it for several weeks, hoping all would be revealed, but in the end decided my time would be better spent developing my artistic skills...