Parkinson's disease (PD) is characterised by an insidious onset with slowing of emotional and voluntary movement, muscular rigidity, postural abnormality and tremor. Parkinson's disease was first described in 1817 by James Parkinson. It is a progressive, neurological disease mainly affecting people over the age of 50, although at least 10% of cases occur at an earlier age. It affects people of either sex or all ethnic groups. In the normal brain, some nerve cells produce the chemical dopamine, which transmits signals within the brain to produce smooth movement of muscles. In Parkinson's patients, 80 percent or more of these dopamine-producing cells are damaged, dead, or otherwise degenerated. This causes the nerve cells to fire wildly, leaving patients unable to control their movements. This book examines new research results from around the world.