A comprehensive and clear text
It is the only text dealing both with the theory of one-dimensional and multidimensional linear singular integral operator, covering both Mikhlin's theory and Calderon-Zygmnund and Stein's theory. It also presents some mainstream topics like pseudodifferential operators and some not easily foun ones like systems of singular integral equations (in one and more space dimensions) and numerical
methods for singular integral equations. The writing style is plain as usual for Mikhlin.