Developments of microcalorimeters for combustion, heat capacity, and solution calorimetry that have been done in our Society over the past four decades are surveyed. Unique experimental results obtained for several equilibrium and nonequilibrium systems are reviewed in some details. Molecular systems are the main of these topics, hoping that the description reflects the development of other fields in our Society, including metals, inorganic and organic substances, synthetic polymers, and biological materials. Some remarks for further works based on personal experiences are given in this article.