: Covers limits, the number concept (rational vs. real numbers), and the fundamental ideas of integral and differential calculus.

is a foundational mathematical work by Richard Courant and Fritz John . Originally a revision of Courant’s earlier Differential and Integral Calculus , this two-volume set is celebrated for balancing rigorous mathematical proofs with intuitive, application-heavy explanations. Volume I: Single Variable Calculus

Volume I focuses on functions of a single variable, bridging the gap between basic calculus and higher-level real analysis. It is widely used for its clear pedagogical approach and historical context.

: Includes Taylor's expansions, numerical methods, infinite sums/products, and trigonometric (Fourier) series. Volume II: Several Variables