Motor neuron disease (MND), also commonly known as amyotrophic lateral sclerosis (ALS), is a chronic neurodegenerative disorder of the motor system in adults, characterised by the loss of motor neurons in the cortex, brain stem and spinal cord. This book presents current research from across the globe in the study of the causes, classification and treatments of MND, including membrane trafficking defects as determinants of motor neuron susceptibility and degeneration in ALS, motorneuron specific calcium dysregulation and perturbed cellular calcium homeostasis in ALS, stem cells and their application in ALS treatment, excitotoxicity and selective motor neuron degeneration and therapeutic invervention and assistive technology treatments.