A brief book on theoretical neuropsychology, carrying previously unknown theories, written mainly for the layman. Alzheimer's disease, the costliest disease to society, is rapidly increasing in prevalence. It may well be called the pandemic of modern times, wreaking havoc on the elderly people (some as young as 40) of the developed nations, especially America. With only a few weak hypotheses, the cause of dementia is not understood; all proposed medicines have either failed clinical trials or have proven ineffective. This book carries a much stronger, relatively broad-based theory of dementia causation. Our model supports a much-overlooked 1989 theory by Matsuyama about how pervasive Microtubule collapse causes Alzheimer's disease. The model reveals that the brain's psychological functions are carried out by neuro-circuital systems containing myriads of Dopaminergic and Norepic microsystems; it proposes that, due to greater (heat?) burden upon the microtubules due to excessive electrical signalling in the type of brain that is dominated by Dopaminergic subsystems -- the microtubules break down, causing Alzheimer's disease and various other problems.