Andrew Maczek, until his retirement, was a Senior Lecturer in Physical Chemistry at the University of Sheffield, where his research focused on the thermophysical behaviour of fluids. He obtained his first degree in Chemistry at the University of Oxford, where he stayed on to obtain his DPhil in Inorganic Chemistry with Courtney Philips. During a postdoctoral period at the University of Leeds he came under the influence of Peter Gray and happily converted to become a physical chemist. The first edition of this Primer was written during the years while he was actively engaged in academic pursuits at Sheffield.Anthony Meijer is a reader in Theoretical Chemistry at the University of Sheffield, where he and his research group work on the theoretical study of chemical reactions using both electronic structure and quantum dynamics methods for a wide variety of systems from the formation of molecules in the interstellar medium to the vibrational control of electronically excited states. He obtained an MSc in Chemistry from the University of Utrecht before obtaining a PhD with Ad van der Avoird at the University of Nijmegen. He has been at Sheffield for the past 13 years.

• 1: The Boltzmann law 2: Sum over states: the molecular partition function 3: Applications of the molecular partition function 4: From molecule to mole: the canonical partition function 5: Distinguishable and indistinguishable particles 6: Two-level systems: a case study 7: Thermodynamic functions: towards a statistical toolkit 8: The ideal monatomic gas: the translational partition function 9: The ideal diatomic gas: internal degrees of freedom 10: The ideal diatomic gas: the rotational partition function 11: ortho and para spin states: a case study 12: The ideal diatomic gas: the vibrational partition function 13: The electronic partition function 14: Heat capacity and Third Law entropy: two case studies 15: Calculating equilibrium constants Questions and Problems Additional Mathematical Aspects

The approachability of the text and the angle adopted by the authors makes the book a useful reference for my course.