This book constitutes the first volume of a two-volume intellectual biography of Auguste Comte, the founder of modern sociology and a philosophical movement called positivism. Volume One offers a reinterpretation of Comte's 'first career' (1798–1842), when he completed the scientific foundation of his philosophy. It describes the interplay between Comte's ideas and the historical context of post-revolutionary France, his struggles with poverty and mental illness, and his volatile relationships with friends, family and colleagues, including such famous contemporaries as Saint-Simon, the Saint-Simonians, Guizot and John Stuart Mill. Pickering shows that the man who called for a new social philosophy based on the sciences was not only ill at ease in the most basic human relationships, but also profoundly questioned the ability of the purely scientific spirit to regenerate the political and social world.