The study of how national culture, disciplinary tradition, epistemological choice and political expediency affect the construction of collective memory is addressed in this text. It also looks at how historians work with or against those constructions. The text includes essays that focus on a variety of commemorative rites, the quincentenary of Copernicus, the centennials of Pasteur, Darwin and Planck, the tercentenary of Harvard, the half centennial of Los Alamos, the centennial of evolutionary theory and anniversaries of research schools in molecular biology among them.