A short, easily understandable account of Alzheimer's, by world expert Dr Andrew Lees

Britain like the rest of the developed world is in the grip of a silent plague. Its thousands of victims can no longer make sense of the world and are contained for their own safety in fading Victorian piles and nondescript redbrick detention centres around the country. For them the present is a foreign country and the past a lost continent.

There are now more people in the UK with Alzheimer's than the population of Liverpool, and four million Americans are reported to have the disease. Longevity is a major factor in the increasing incidence of the disease, with the number of over 65s in the UK having trebled in the last 100 years, and forecast to double again in the next 25 years. With such an alarming background, the race to find the causes - and therefore potentially a cure - for Alzheimer's is urgent.

In this Penguin Special, Dr Andrew Lees, a world expert on the neurodegenerative diseases explains what we know, and don't know, about Alzheimer's and its amelioration.

Dr Andrew Lees is Professor of Neurology at the National Hospital for Neurology and Neurosurgery, London, and Clinical Director of the Queen Square Brain Bank for Neurological Disorders. His major scientific research has been carried out in the field of dementias and Parkinson's disease. A native of St Helens, Lancashire, he lives in north London.