This book provides an accessible introduction to numerical methods for solving systems of polynomial equations. Similar to how numerical linear algebra turns theorems from linear algebra into floating-point algorithms, numerical algebraic geometry turns theorems from algebraic geometry into numerical algorithms for representing, locating, and manipulating nonlinear algebraic sets. Numerical Algebraic Geometry begins with an introduction to polynomials and numerics, then carefully builds from a single polynomial in a single variable to isolated solutions of multivariate polynomial systems and ultimately to the computation of positive-dimensional irreducible components. Chapters on applications and advanced topics round out the picture. Exercises are provided throughout both for instructors to assign as homework problems and for readers to deepen their understanding. Assuming only a background in multivariate calculus and linear algebra, this book would be suitable for an upper-level undergraduate course, motivated undergraduate math majors seeking an independent project, and everyone interested in learning more about numerical algebraic geometry.