This self-contained introduction to the behavior of several spectral characteristics of large Toeplitz band matrices is the first systematic presentation of a relatively large body of knowledge, covering everything from classic results to the most recent developments. The spectral characteristics include determinants, eigenvalues and eigenvectors, pseudospectra and pseudomodes, singular values, norms, and condition numbers. Toeplitz matrices emerge in many applications and the literature on them is immense. They remain an active field of research with many facets, and the material on banded ones until now has primarily been found in research papers. The book may serve both as an introductory text and as a reference. The approach is based on the experience of the authors in combining functional analytical methods with hard analysis, and in applying operator theoretical methods to matrix theory, revealing the essence of several phenomena and leading to significant improvements in existing results.