Book excerpt: This book talks about the multidimensional biological etiology of Alzheimer’s disease and autism spectrum disorder which leads to distinctive ways of perception, thinking and learning in affected individuals. It provides a deeper emphasis on the need for early diagnosis, continuous assessment of patients and the proper educational methods and environment required towards enabling people affected with these disorders capable of evolving and learning. This book explores alternative solutions for autism spectrum disorder based on the theory of brain plasticity, the relationship between the gut microbiota and the central nervous system along with genetic factors and toxic metal exposures which are responsible for the oxidative damage resulting in a decreased ability of the patients to use objects or response to auditory stimuli. It also identifies and provides the latest research towards dealing with memory loss, which is the first sign of cognitive impairment followed by behavioral disturbances. These symptoms are associated with a rigorous neuronal decline and the appearance of two brain lesions, senile plaques and neurofibrillary tangles, which are mainly composed of Aβ and hyper phosphorylated tau protein respectively. This book also provides the latest research towards reducing autism disorder severity such as targeting the disease with symptomatic treatments such as cholinesterase inhibitors, NMDA receptor antagonist, β-secretase and γ-secretase inhibitors, α-secretase stimulators, tau inhibitors, immunotherapy, nutraceuticals, and nano drugs. This book will not only be a good resource for professors and lecturers teaching in the area of neuroscience, medicine, biochemistry, neuroinformatics, and nanotechnology, etc. but also for professionals working in the field of occupational therapy and geriatric clinics and rehabilitation.