Many developing fields of science and engineering, including nanotechnology, protein engineering, microfluidics, etc., require an in-depth molecular understanding and description of matter. Molecular approaches allow for creative design and analysis of systems by altering molecular properties to achieve desired outcomes. This book provides molecular and statistical mechanical basis for the classical fundamental molecular description of matter, and the laws associated with transport phenomena and thermodynamics. The content of Molecular Thermodynamics and Transport Phenomena: Complexities of Scales in Space and Time, Second Edition was expanded and includes multicomponent and multiphase systems, which are important in all aspects of process analysis and design including energy efficiency. In addition, the programming parts of this text have been switched to Python because of its open-source nature and ubiquitous use across science and engineering.