“This volume is an interesting contribution to a field that still holds a lots of secrets. It will be of great interest to experts.” (Ch. Baxa, Monatshefte für Mathematik, Vol. 198 (2), June, 2022)“What makes this book a unique is that it systematically covers effective computation of the spectral terms of the selberg trace formula, namely the eigenvectors, eigenfunctions and resonances. ... The computation of this book gives us a hint as to what actually occurs with the extremely complicated limit … The book is self-contained, covering both the theoretical background and the numerical aspects.” (Joshua S. Friedman, Mathematical Reviews, May, 2018)