This book provides an introduction to functional analysis with an
emphasis on the theory of linear operators and its application to
differential equations, integral equations, infinite systems of linear
equations, approximation theory, and numerical analysis. As textbook
designed for senior undergraduate and graduate students, it begins with
the geometry of Hilbert spaces and proceeds to the theory of linear
operators on these spaces including Banach spaces. Presented as a
natural continuation of linear algebra, the book provides a firm
foundation in operator theory which is an essential part of mathematical
training for students of mathematics, engineering, and other technical
sciences.