 As in Book One, Descartes uses the Pappus Problem to illustrate the power of his geometrical calculus, where in Book Two, his aim is to show how his algebraic classification of curves makes it easy “to demonstrate the solution which [he has] already given of the problem of Pappus” (G, 59). The specific goal here is to establish that the curves which solve the general Pappus Problem are legitimately geometrical curves, i.e., to show that the Pappus curves meet the exact and rigorous standards of geometrical construction that he has just laid out. Descartes’ discussion of the Pappus Problem in Book Two begins as follows: