The progress that has recently been made in the field and applications of thermochemistry, having as a consequence an in­ crease in the interest of the subject, undoubtedly can be con­ sidered highly remarkable. Traditionally, the thermochemist has provided accurate ther­ mal data on chemicaZ compounds of practicaZ importance, mainly by calorimetric and by equilibrium studies. The scope has been considerably extended in recent years, following the development of microcalorimetric techniques, of flow calorimetry, of titra­ tion calorimetry, and of high temperature calorimetry. The im­ pact has been most noticeable in biochemical studies, in metallur­ gical studies, and in organometallic and inorganic thermochemis­ try. A parallel