Linear Methods of Applied Mathematics - This is a WWW textbook written by Evans M. Harrell II and James V. Herod, both of Georgia Tech. It is suitable for a first course on partial differential equations, Fourier series and special functions, and integral equations. Students are expected to have completed two years of calculus and an introduction to ordinary differential equations and vector spaces. Topics include Fourier series, Green's functions, and PDEs.
Mathematical Methods in Physics - Covers Conformal Field Theory, Modular Functor, Topological Quantum Field Theory and Frobenius Algebras, Operads, Homotyopy Algebra.
Methods in Mathematical Physics - Covers Complex variables, special functions, second order linear ODEs, asymptotic expansions, Laplace transforms. (One large PS file)