Preliminaries; 1. Vector spaces; 2. Bases and similarity; 3. Block matrices; 4. Inner product spaces; 5. Orthonormal vectors; 6. Unitary matrices; 7. Orthogonal complements and orthogonal projections; 8. Eigenvalues, eigenvectors, and geometric multiplicity; 9. The characteristic polynomial and algebraic multiplicity; 10. Unitary triangularization and block diagonalization; 11. Jordan canonical form; 12. Normal matrices and the spectral theorem; 13. Positive semidefinite matrices; 14. The singular value and polar decompositions; 15. Singular values and the spectral norm; 16. Interlacing and inertia; Appendix A. Complex numbers.