Four calorimetric techniques -- Oxygen Bomb, Fluorine Bomb, Solution, and Levitation Calorimetry -- were applied to obtain new thermochemical data for a variety of organic and inorganic compounds. Oxygen bomb calorimetry measurements were performed on the following compounds and the enthalpies of formation obtained for 2,2,4-trimethylpentane, meta- and parabenzodicyclopentene, 1,5-diphenylnaphthalene, and 2,3-diazabicyclo[2.2.2]oct-2-ene are: -258.28 + 5.18, -53.6 ± 1.62, -9.18 ± 1.7, 216.12 ± 5.87, and 13.39 ± 1.55 kJ mole, respectively. Enthalpy of formation measurements made on coal model compounds (naphthalene, biphenyl, phenanthrene, 2-methylnaphthalene, 1,2,3,4-tetrahydronaphthalene, and 2-ethylnaphthalene) gave the following values: 77.63 ± .75, 99.66 ± .67, 116.19 ± 1.66, 32.87 ± .71, -64.14 ± 2.17, and -76.92 ± 1.76 kJ mole, respectively. Fluorine bomb calorimetry was used to obtain high precision values for the enthalpies of formation of SFg(g) and SiF4(g) as -122.83 ± .64 and -1611.6 ± 1.32 kJ mole, respectively. The compounds molybdenum diselenide and tetraarsenic tetrasulfide were burned in fluorine to obtain enthalpies of formation of -236.4 ± 1.31 and -132.92 ± 6.4r respectively. Solution calorimetry was performed on the compounds: lithium oxide, cesium bromide, and potassium acid phthalate to establish their enthalpies of solution as -131.746 ± .14, 26.143 ± .43, and -156.5 ± .59 kJ mole-1, respectively. Levitation calorimetric studies of liquid tungsten indicate the enthalpy of fusion of tungsten to be 52. ± 2.3 kJ mole.