MPSpack: A MATLAB Toolbox to Solve Helmholtz PDE, Wave Scattering, and Eigenvalue Problems Using Particular Solutions and Integral Equations. MPSpack is a user-friendly and fully object-oriented MATLAB toolbox that implements the method of particular solutions, nonpolynomial FEM, the method of fundamental solutions, and integral equation methods, for the efficient and highly accurate solution of Laplace eigenvalue problems, interior/exterior Helmholtz boundary-value problems (e.g. wave scattering), periodic diffraction problems, and related PDE problems, on piecewise-homogeneous 2D domains.