THE AIM OF THIS CHAPTER IS TO BRIEFLY PRESENT SIX ANALYTICAL METHODS for characterizing hydrocarbon compounds found in fuels and lubricants. The methods presented are NMR spectrometry, gas chromatography, liquid chromatography, ultraviolet spectroscopy, mass spectrometry, and infrared spectroscopy. The analysis of hydrocarbons deploying these methods is well-founded in scientific laboratories and is the basis of numerous ASTM standards.