This is one of those rare books that takes something potentially dry—a 20th-century mathematician's biography—and makes it sing. Heiligman and Pham don't dumb down Erdős or his eccentricities; they celebrate him as a person who lived exactly how he wanted, traveled the world, and collaborated on thousands of mathematical papers.

What makes this work is the balance: it's respectful of his genius without being stuffy, and honest about his quirks (he had his mom butter his bread until he was 20!) without mocking him. For kids who love math, this is validation. For kids who don't, it's a window into a completely different way of thinking about numbers.

The 4.7 Amazon rating and multiple best-of-year recognitions aren't flukes. This is a genuinely enriching picture book that expands what kids think a mathematician—or any person—can be.