Linear Operators. Part II: Spectral Theory. Self Adjoint Operators in Hilbert Space by Nelson James Dunford, Jacob T. Schwartz
English | 1963 | ISBN: 0470226382 | 1072 Pages | PDF | 38.2 MB
Maybe it is not suitable as an introductory book on functional analysis. However, for those of us who need applicable functional analysis from PDE's to dynamical systems and beyond, there is no better reference.