Pyrolysis is degradation of biomass by heat in the absence of oxygen which results in the production of liquid, gaseous, and solid products. Conversion of biomass materials composed predominantly of holocellulose and lignin using pyrolysis type reactions represents a promising option for the production of fuels and chemicals. The hemicelluloses degrade first at temperatures of 470 to 530 K and cellulose follows in the temperature range of 510 to 620 K, with lignin being the last component to pyrolyse at temperatures of 550 to 770 K. If the purpose is to maximize the yield of liquid products resulting from biomass pyrolysis, a low temperature, high heating rate, short gas residence time process would be required. If the purpose were to maximize the yield of fuel gas resulting from pyrolysis, a high temperature, low heating rate, long gas residence time process would be preferred. For a high char production, a low temperature, low heating rate process would be chosen. Pyrolysis of lignocellulosic biomass materials has been found to be a promising method for producing pyrolytic oils also known as bio-oil.