What is the most influential book on Earth?

If you were going to make a list of the top ten most influential books ever written I think there'd be some fairly straightforward inclusions; The Quran, The Bible, Darwin's The Origin of Species and Einstein's Theory of Relativity amongst others. A less obvious inclusion might be the Diagnostic and Statistical Manual of Mental Disorders (usually referred to as the DSM). This book contains lists of symptoms which then define specific mental disorders and is used by the American Psychiatric Association and many UK based institutions.

The power of the DSM is in its ability to 'create' new mental disorders (as well as revise existing disorders) and as many of you know having studied the legal, social and personal ramifications of dealing with a mental health diagnosis, the fallout can be profound.

In the last week the DSM has become controversial all over again when details of the proposed new edition (DSM 5) started to emerge. This will have consequences for anyone working with people who have a mental health diagnosis and under the new guidelines a number of new symptoms have been medicalised as possible disorders. Amongst these are shyness in childhood and feelings of grief following bereavement.

As a psychology graduate whose course was heavily influenced by social constructionist principles, I find the issues surrounding diagnosis and stigma absolutely fascinating. Have a look at The Guardian if you'd like to read more on the current DSM 5 situation.