From the reviews:

„The core of the book under review is devoted to the detailed description of the Guillopé-Zworski papers … . The exposition is very clear and thorough, and essentially self-contained; the proofs are detailed … . The book gathers together some material which is not always easily available in the literature … . To conclude, the book is certainly at a level accessible to graduate students and researchers from a rather large range of fields. Clearly, the reader … would certainly benefit greatly from it.“ (Colin Guillarmou, Mathematical Reviews, Issue 2008 h)