One of the great themes of self-help literature is the need to be free of unconsciously accepted habits and norms. Langer's classic shows how we can actually accomplish it. A Harvard psychology professor, her research into rigidity of mind led to observations about mental fluidity, or mindfulness.

The book is in the best tradition of Western scientific research, filled with the results of fascinating experiments which should appeal to those readers who enjoy Emotional Intelligence or Learned Optimism.

Who or what is a mindful person? Langer suggests that their qualities will include:

• Ability to create new categories;
• Openness to new information;
• Awareness of more than one perspective;
• Attention to process (doing) rather than outcome (results); and
• Trust of intuition.

To look at the first: Langer says we live and experience reality in a conceptual form; we don't see things afresh and anew every time we look at them. Instead, we create categories and let things fall into them, which is a more convenient way of dealing with the world. Apart from the smaller things, such as defining a vase as a Japanese vase, a flower as an orchid or a person a boss, there are the wider categorisations under which we live including religions, ideologies and systems of government. Each gives us a level of psychological certainty and saves us from the effort of constantly challenging our own beliefs. We divide animals into 'pets' and 'livestock' so that we can feel OK loving one and eating the other.

Mindlessness results when we don't know that the categories we subscribe to are categories, and have accepted them as our own without really thinking. Creating new categories, and reassessing old ones, is mindfulness. Or as William James put it: 'Genius...means little more than the faculty of perceiving in an unhabitual way.'

In essence, mindfulness is about preserving our individuality. By choosing the mindset of limited resources, by choosing to focus on outcomes rather than doing (process), and by making faulty comparisons with others, we become little more than robots. The true individual is characterised by openness to the new, is always reclassifying the meaning of knowledge and experience, and has the ability to see their daily actions in a bigger, consciously chosen perspective.

Langer recognises the parallels in her work with Eastern religion; for example, the Buddhist understanding that meditation is about enjoying a mindful state which leads to 'right action'. Its ideas may seem difficult, but Mindfulness was written for a popular audience and is quite short. It has none of the hoopla common to self-help writing; people value it for its fine distinctions and insights based on years of research, and like it for its understatedness.