In Pursuit of the Unknown: 17 Equations That Changed the World, by Ian Stewart.
Stewart explores a variety of important equations, including:
- Pythagorean theorem,
- the normal curve,
- Newton’s Law of Gravity,
- Fourier transforms,
- Black-Scholes
Each equation gets a little one-page summary, and a chapter of explanation. I can’t say I could re-trace every step of the math and physics, but the explanations were interesting and intuitive enough that I didn’t feel lost. These equations and their stories give you a feel for beauty in mathematics.