This book gives an introduction to functional analysis for graduate students pursuing research involving numerical analysis‎.‎ The text covers basic results of functional analysis as well as additional topics needed in theoretical numerical analysis‎.‎ Applications of this functional analysis are given by considering numerical methods for solving partial differential equations and integral equations‎.‎ Extensive exercises are included at the end of each section along with recommendations for additional reading‎.‎ This book is especially suited to students interested in the numerical solution of differential and/or integral equations‎,‎ but it will appeal to numerical analysts and mathematically‎-oriented students and researchers in engineering‎,‎ physics‎,‎ and related areas‎.‎