In Pursuit of the Unknown by Ian Stewart, 2012, ISBN 978-0-465-02973-0. Subtitle: 17 Equations That Changed the World. This book has a label on the back the says Mathematics, but I think it should be labelled Physics, etc. It is really more about the subjects of the equations than the mathematics. Subjects discusses include Pythagora's Theorem, Logarithms, Calculus, Newton's Law of Gravity, Square Root of Minus One, Euler's Formula for Polyhedra, Normal Distribution, Wave Equation, Fourier Transform, Navier-Stokes Equation, Maxwell's Equations, Second Law of Thermodynamics, Relativity, Schrodingers Equation, Information Theory, Chaos Theory and Black-Scholes Equation.
If you are interested in how mathematics is used in the real world, I think this is a good introduction. It is well written, informative and I think entertaining. Sadly there is no list of books for further reading.
 Purchased from Amazon on 2013-3-7 for $20.51.