Titu Andreescu is widely regarded as one of the premier authors in the world of competitive mathematics

Many of Andreescu's books are highly regarded for their problem-solving methodology: Mathematical Olympiad Treasures

Mathematical Olympiad Treasures:

An entry-level guide that introduces the four main pillars: Algebra, Geometry, Number Theory, and Combinatorics.

Notable Titu Andreescu Books

AM-GM Inequality

Explain a specific concept like or Pigeonhole Principle . 101 PROBLEMS IN ALGEBRA - mathematical olympiads

1. "USA Mathematical Olympiads 1972–1986" – Historical problems with Andreescu’s commentary.
2. "The IMO Compendium" (co-edited) – Every IMO problem from 1959 to 2009. The ultimate reference.
3. "Complex Numbers from A to Z" (with D. Andrica) – Better than 90% of university complex analysis texts for olympiad geometry.
4. "An Introduction to Diophantine Equations" (with D. Andrica) – Covers the "Vieta jumping" technique better than any other source.
5. "Mathematical Bridges" (with C. Mortici) – For students transitioning from high school to undergraduate research.