"The Uncertainty in Physical Measurements" is a specialized book that addresses the fundamental role of uncertainties in physical measurements. It provides a comprehensive introduction to the concepts of uncertainty assessment and data analysis, which are crucial for understanding physical laws and their technological applications. The book is primarily aimed at students of the natural sciences, but it is also a valuable resource for researchers and educators in schools. It has been tested and refined over several years in teaching to ensure a user-friendly and pedagogically valuable approach. The structure of the book includes a detailed introduction to measurement and uncertainty, followed by common procedures for data analysis. The combination of theoretical foundations and practical applications makes it an indispensable guide for anyone dealing with physical measurements and their uncertainties.