A Boundary Integral Equation Package. BIEPACK is a package of programs, written in Fortran 77, which can be used to solve integral equations defined over a surface S in R3. The package contains two kinds of programs. First, utility programs are given to help with the creation and refinement of triangulations over the surface of S, numerical integration, interpolation, and approximation over S, and approximation of S using quadratic interpolation. Other utilities are also included. The second kind of program in the package is to carry out the solution of particular types of integral equations. For example, the program neumann_ell.f solves a second kind integral equation that is a reformulation of the exterior Neumann problem for Laplace’s equation over an ellipse, and the program is easily modified for other surfaces.