You are reading this book on behalf of your dog. While pet owners experience immense stress due to the onset of this disease, one thing must not be forgotten: he is the true victim and the primary patient. Like humans, dogs have gained life expectancy over the past decades. This comes with a pathological impairment of their best abilities. In our four-legged friends, senile dementia is an increasingly common age-related condition. Two main types are distinguished: Alzheimer’s dementia caused by the death of nerve cells and the variant caused by circulatory disorders, which leads to cognitive losses. Both causes can also occur simultaneously. The information published here is intended to improve the daily lives of our ailing four-legged companions.