If someone you know is behaving differently from usual, you might be tempted to blame their hormones. But how much can such changes be put down to this cause. Quite a lot, according to this new book by Vivienne Parry. But the book isn't just about finding reasons for people's behaviour, hormones are important to all of us, and it is vital to be able to judge hormone-related medical treatments that are becoming available. Are they treating specific medical conditions, or are they more about lifestyle choices. This book supplies plenty of information to help you make up your mind.

From the moment of our conception hormones are influencing the course of our lives. Changes in hormone levels while we are still in the womb play a large part in what we become later in our lives, and in particular in the differences between male and female behaviour. Moreover, the timing of different stages of pregnancy and the birth is controlled by hormones. For a few years during childhood the role of hormones seems to subside a little. But then come the teenage years. Staying in bed until the afternoon, a great interest in sex and arguing with parents. Parry has two teenage boys, and so knows about the unpredictable behaviour of this age group, explaining how much of this can be put down to hormones. As part of this she looks at the role of testosterone, and whether is it to blame for aggressive behaviour.

This book is written by a woman, and I would say that it is primarily aimed at women readers. Clearly the hormones of most interest in health terms are those controlling the female reproductive cycle, but the effects of hormones in men are also looked at from the point of view of a wife or mother. Some adult education colleges offer women's health courses, and if a man should accidentally turn up at one he would probably be rather embarrassed. I sometimes had a feeling of this sort while reading this book. But the importance of women's health issues means that there will be many readers who find this book useful, especially those who are looking into the effectiveness of hormone treatments. In particular there is a chapter dedicated to the subject of the menopause and the successes and potential problems of Hormone Replacement Therapy.

I wouldn't like to give the impression that this book is just about women's reproductive hormones. I found the last few chapters of the book the most interesting, as they moved away from sex and reproduction, and on to the involvement of hormones in other parts of our lives. Hormones have an important role in appetite modulation and so can be responsible for whether or not we put on weight. They also play a part in the timing of our lives. Our daily cycles are regulated by hormones, and this book explains what happens when these cycles are upset. In the longer term, our ageing process is related to hormone levels. Any procedures which claim to slow down ageing are bound to have a wide following, and this book will help you to evaluate which are likely to have some promise and which are just wishful thinking.

This book has been shortlisted for the 2006 Aventis science book prize, but I feel that it is unlikely to win. Firstly, in my search for reviews on the web, this book seemed to have the fewest of the six on the list, and one of those found it to be dull. I wouldn't say that, although I did feel that the author relied too much on maintaining the readers interest by writing about issues relating to sex . The main reason that I wouldn't choose it as the final winner is that it seems to be more in the category of 'Health' rather than 'Popular Science'. It doesn't go much into the actual chemistry of hormones, rather it describes what effects hormones have on us. The first chapter is called 'A bluffer's guide to hormones' and introduces some of the science involved, but I felt that the rest of book could have got along without this - it can be read without needing any prior knowledge of the subject. Parry has written for several prominent newspapers, and I would say that the main strength of the book is in its providing a balanced viewpoint on a topic where there is often a lot of media hype.