Engel and Reid's Quantum Chemistry and Spectroscopy gives students a contemporary and accurate overview of physical chemistry while focusing on basic principles that unite the sub-disciplines of the field. The Third Edition continues to emphasize fundamental concepts and presents cutting-edge research developments that demonstrate the vibrancy of physical chemistry today. MasteringChemistry(R) for Physical Chemistry - a comprehensive online homework and tutorial system specific to Physical Chemistry - is available for the first time with Engel and Reid to reinforce students' understanding of complex theory and to build problem-solving skills throughout the course.