The word dyslexia comes from Greek and means "difficulty with words". It is best described as a difference in the part of the brain that deals with language, and affects the underlying skills that are needed for learning to read, write and spell. Brain imaging techniques show that dyslexic people process information differently, often having difficulty with sequences, reading and time management. As dyslexia is neurologically based, children are born with the condition. However, it is only when they begin to learn to use words and symbols that it becomes a noticeable problem.

Young children may begin to talk later than their contemporaries and have difficulty pronouncing words. Older children often rely heavily on memorising rather than understanding, while adults with dyslexia tend to work slowly and try to avoid writing.

Between 4% and 5% of the British population have dyslexia, with around two million people severely affected. The condition affects males and females almost equally.

Although it can often be mistaken for a lack of motivation or emotional difficulties, many people who are dyslexic are of above average intelligence, with a number having distinctive talents. In fact, there is a hypothesis that neurological anomalies also give some dyslexic people visual, spatial and lateral thinking abilities that enable them to be great problem solvers or creative talents.

Many great thinkers had dyslexia, including Albert Einstein, Thomas Edison and Leonardo da Vinci, as did others ranging from Charles Rennie Mackintosh to Winston Churchill. Today, Richard Branson, Eddie Izzard, Keanu Reeves, Guy Ritchie and Jodie Kidd are among the celebrities who have spoken about their dyslexia. Oscar winner Whoopi Goldberg admitted that she was considered "retarded" for years, while Tom Cruise confessed, "I felt really embarrassed" when it came to dealing with his dyslexia. He now teaches his own children to read.

"It's great that figures in the public eye are coming forward and talking positively about their experiences with dyslexia," says David Anderson of the British Dyslexia Association. "It shows everyone, and especially those with dyslexia, that they too can be successful in whatever they put their minds to."