<p>This book presents the combined proceedings of the 17th International Conference on Computer Science and its Applications (CSA 2025) in Phu Quoc, Vietnam, December 18–20, 2025. This proceedings reflects the state of the art in the development of computational methods, involving theory, algorithms, numerical simulation, error and uncertainty analysis, and novel applications of new processing techniques in engineering, science, and other disciplines related to ubiquitous computing.</p>