Calorimetry and thermodynamic studies have long been playing a very important role in the research fields of fundamental science and technology. Some topics and examples of thermodynamics studies are given. and the details are explained on the basis of the present author's experience, focusing attention to application of adiabatic calorimetry and thermodynamics to solve critical problems in materials science: (1) condensed gas calorimetry and third law entropy, (2) phase transition and polymorphism in simple molecular crystals. (3) incommensurate phase transitions, (4) particle size effects on the phase transitions in ferroelectric/ferroelastic crystals, (5) relaxor ferroelectrics and multi-ferroics, and some other topics in materials science and technology. (C) 2008 Elsevier Ltd. All rights reserved.