NOVELTY - A thermally stable bio-oil composition (C1) derived from a cellulosic biomass, where the composition (C1): (a) has an oxygen content not greater than 30 wt.%, (b) has a water content of less than 6 wt.%, (c) has a Conradson Carbon number of less than 25 wt.%, and (d) has a total acid number of not greater than 30 mgKOH/g.    USE - As a thermally stable bio-oil composition derived from a cellulosic biomass, preferably lignocellulosic biomass (claimed); useful as a fuel without having to undergo deoxygenating processes such as hydrotreating; and as fuel for clean, controlled combustion in boilers and in diesel and stationary turbines.    ADVANTAGE - The thermally stable bio-oil composition derived from a cellulosic biomass has: an oxygen content of 7-15 wt.%, a water content of 1-4 wt.%, a carboxylic acid content of less than 2000 ppm, contains less than 4 wt.% of compounds having a carbonyl group, a Conradson Carbon number of less than 22 wt.%, and a total acid number of less than 20 mgKOH/g. The bio-oil composition has: a stability parameter of less than 30, not greater than 20, not greater than 15, or not greater than 10 cp/hour, an oxygen content of not greater than 30 wt.%, or 7-15 wt.%, a water content of less than 6 wt.%, or 1-4 wt.%, a Conradson Carbon number of less than 25 wt.%, and a total acid number of not greater than 30 mgKOH/g or less than 20 mgKOH/g, a carboxylic acid content of less than 2000 ppm, contains less than 4 wt.% of compounds having a carbonyl group, a Conradson Carbon number of less than 22 wt.%, and has a total acid number of less than 20 mgKOH/g. The bio-oil composition has: chemical and physical properties that make it more cost effective; result in a particularly stable bio-oil; a stability that enhances their ability to be transported; and increased thermal stability and lower corrosiveness in comparison to pyrolysis derived bio-oils.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for producing the composition (C1) derived from a cellulosic biomass, involving: (a) converting at least a portion of the cellulosic biomass material in an oxygen-poor environment in the presence of a catalyst material at a temperature of 200-1000 degrees C to produce a reaction product stream containing the composition (C1); and (b) separating the composition (C1) from the reaction product stream such that the composition (C1) (i) has an oxygen content of not greater than 30 wt.%, (ii) has a water content of less than 6 wt.%, (iii) has a Conradson Carbon number of less than 25 wt.%, and (iv) has a total acid number of not greater than 30 mgKOH/g, and where characteristics (i)-(iv) are achieved without an oxygen-removing hydrotreatment step.