Hyperbolic Geometry (Springer Undergraduate Mathematics Series)

The Geometer's Sketchpad: Dynamic Geometry Software for Exploring Mathematics

Trigonometry

Low-Dimensional Geometry (Student Mathematical Library: IAS/Park City Mathematical Subseries)

Algebraic Curves and Riemann Surfaces (Graduate Studies in Mathematics, Vol 5)

The Road to Reality: A Complete Guide to the Laws of the Universe

Calculus On Manifolds: A Modern Approach To Classical Theorems Of Advanced Calculus

Dynamical Systems (Dover Books on Mathematics)

Geometry: Euclid and Beyond (Undergraduate Texts in Mathematics)

Category Theory for the Sciences (MIT Press)

Linear Algebra Done Right (Undergraduate Texts in Mathematics)

Algebra (Graduate Texts in Mathematics)

Categories for the Working Mathematician (Graduate Texts in Mathematics)