A mathematician, a social reformer within Saint-Simon's utopian-socialist movement, and later a prosperous banker, Olinde Rodrigues is a fascinating figure of the city of Paris in the first half of the nineteenth century. Since archival resources on Rodrigues are not abundant and since they are scattered throughout a variety of archives studying him presents difficult historiographic challenges. These are met for the first time in this book, written by a team of mathematicians, historians of mathematics, and historians of culture and society for people interested in any of these fields.