I. Quasi-historical introductionII. Remarks on unique factorizationIII. Elementary methodsIV. Kummer's argumentsV. Why do we believe Wiles? More quasi-historyVI. Diophantus and FermatVII. A child's introduction to elliptic functionsVIII. Local and globalIX. CurvesX. Modular formsXI. The Modularity ConjectureXII. The functional equationXIII. Zeta functions and L-seriesXIV. The ABC-ConjectureXV. HeightsXVI. Class number of imaginary quadratic number fieldsXVII. Wiles' proof