"The 'X-ray Photoelectron Spectroscopy (XPS) - A Foundation' is a specialized book that focuses on the technique of X-ray photoelectron spectroscopy. This method allows for the determination of the chemical composition of surfaces through the analysis of photoelectrons generated by X-ray irradiation. The book provides a comprehensive introduction to the fundamentals and applications of this important analytical technique, which is significant in various fields such as materials science, microelectronics, and catalysis. It explains how the energy of the emitted photoelectrons depends on the electronic and chemical configuration of the atoms, leading to valuable information about surface characteristics. The XPS technique is particularly advantageous as it can analyze stable samples under ultra-high vacuum conditions without causing damage. This book is a valuable resource for students and professionals engaged in the characterization of materials and their surfaces.".