The Mathematician's Mind: The Psychology of Invention in the Mathematical Field

Einstein's Legacy: The Unity of Space and Time

Lectures on Cauchy's Problem in Linear Partial Differential Equations

Non-Euclidean Geometry

An Essay on the Psychology of Invention in the Mathematical Field

Geometry: A Very Short Introduction

Geometrical Researches on the Theory of Parallels

Elliptic Integrable Systems: A Comprehensive Geometric Interpretation

Geometry by Construction: Object Creation and Problem-solving in Euclidean and Non-Euclidean Geometries

Multivariable Calculus and Differential Geometry

Tensors and Riemannian Geometry: With Applications to Differential Equations

Special Relativity and Classical Field Theory: The Theoretical Minimum