Sophie's Diary is a mathematical novel inspired by French mathematician SophieGermain. The fictional diary presentsmy perspective of howa young Parisian girl could have learned mathematics in the years between 1789 and 1794. As a work of historical fiction, the chronological setting is real, drawn from the history of the French Revolution, and it describes actual historical persons, but the principal character (Sophie) is fictional, even if inspired by a real person. I attempted to capture the manners and social conditions of the people and time presented in the story, with due attention paid to period detail and fidelity. Moreover, as a mathematical novel Sophie's Diary includes the mathematics that the young character taught herself, interspersed with interludes from the history of mathematics.

Sophie Germain is the first woman in the history of mathematics to make a substantial contribution to the proof of Fermat's Last Theorem, and to the theory of elasticity as well — all that achieved within a time span of 22 years and workingmostly on her own. Overcoming prejudice and numerous obstacles to her scientific endeavors, Sophie Germain became in 1815 the first woman in the history of science to win a prize from the Paris Academy of Sciences.

From her first biographers I inferred that, around 1797, Sophie Germain assumed the name of a male student at the École Polytechnique in Paris, M. LeBlanc, and submitted her own work to Lagrange (1736–1813), one of the greatest mathematicians of the eigtheenth century.