Amyotrophic lateral sclerosis is a neurodegenerative and neuromuscular disease. It affects the motor neurons which control the voluntary muscles. Some of the symptoms of this disease are muscle twitches, stiff muscles, difficulty in swallowing or speaking, and muscle wasting. The treatment of amyotrophic lateral sclerosis involves improving the symptoms. Non-invasive ventilation and mechanical ventilation can be used to prolong life. Genetic and environmental factors can affect the chances of being affected by amyotrophic lateral sclerosis. One of the characteristic features of this disease is the death of lower motor neurons and upper motor neurons. The genes which are considered to be behind amyotrophic lateral sclerosis are classified on the basis of their function into cytoskeleton, protein degradation and RNA processing. This book discusses the fundamentals as well as modern approaches of amytrophic lateral sclerosis. It will also provide interesting topics for research which interested readers can take up. This book will provide comprehensive knowledge to the readers.