In this review article technical aspects of high-pressure Raman spectroscopy are discussed. With the advancements-in the diamond anvil cell (DAC) technology and spectroscopic instrumentation, high-pressure Raman spectroscopy has made tremendous advances. It has become possible to study vibrational spectra of micron size (~5μ) samples of solids, liquids and gases to very high pressures--approaching the megabar range--in the 0°, 90°, 135° and 180° scattering geometries. The advantages and problems of Raman measurements in various scattering geometries in the DAC are examined by comparing: (i) the high-pressure spectra of normal deuterium (n-D2) fluid in 0° and 90° scattering geometries, and (ii) micro-Raman spectra of diamond anvils at high pressures in 135° and 180° scattering geometries. It is found that the 90° and 135° scattering modes of high-pressure Raman measurements in the DAC provide better signal-to-noise ratio and less interference from diamond-anvil fluorescence. In addition, the results of high-pressure Raman measurements of Ge02 and Si02 glasses and of crystalline polymorphs of a number of materials, including Ge02, Si02, and TiO2 are summarized.