This publication is a landmark work commemorating the centennial of Alois Alzheimer's discovery of what would be known as Alzheimer's disease (AD). The centennial of Alois Alzheimer's original description of the disease that would come to bear his name offers a vantage point from which to commemorate the seminal discoveries in the field. It traces how the true importance of AD as the major cause of late life dementia ultimately came to light and narrates the evolution of the concepts related to AD throughout the years and its recognition as a major public health problem, with an estimated 30-40 million people affected by AD today. To identify the breakthroughs, the editors have used citation analysis, landmark papers identified by current researchers, and drew upon their own experience and insights. This process took into account the perspectives of individuals who recall the impact of findings at the time they were made, as well as of scientists today who have the advantage of hindsight in weighing the lasting influence of these findings. Because modern AD research was triggered by the seminal work of Tomlinson, Blessed, and Roth some four decades ago, it is particularly fortunate that the vast majority of these milestone authors are still with us.