Old and New Unsolved Problems in Plane Geometry and Number Theory

This book offers a compelling gateway into the enduring mysteries of mathematics, presenting 24 central unsolved problems in plane geometry and number theory that are accessible even to those with a modest mathematical foundation. The authors, Victor Klee and Stan Wagon, expertly frame each challenge within its historical and mathematical context, making the content suitable for undergraduate-level exploration. The presentation is uniquely structured, with each problem section divided into two parts to systematically unpack the core question and its related variants. It serves as a fascinating tour of the mathematical landscape's unexplored territories.

What distinguishes this work is its masterful balance between intellectual depth and approachability, transforming abstract problems into tangible puzzles that invite reader engagement. It is ideally suited for curious undergraduates, advanced high school students, and any enthusiast eager to understand what lies at the frontiers of mathematical knowledge. By demystifying problems that have resisted solution for decades or even centuries, the book does more than inform—it inspires a deeper appreciation for the living, evolving nature of mathematical inquiry and empowers readers to glimpse the horizon of human understanding.