NOVELTY - Preparation of a product (I) from a material (II) comprising carbon-containing compounds, comprises: converting (II) into at least two intermediates, where at least one intermediate is produced by a biological conversion process and at least one intermediate is produced by a thermochemical conversion process, and reacting at least one biological process-produced intermediate and at least one thermochemical process-produced intermediate to form (I).    USE - The process is useful for producing a product (an alcohol (a monohydric alcohol, or a dihydric alcohol (preferably ethanol, propanol, propylene glycol, butanol, 1,4-butanediol, 1,3-propanediol, or their methyl esters)), a carboxylic acid, a salt of a carboxylic acid, or an ester of a carboxylic acid) from a material comprising carbon-containing compounds, where the material is herbaceous matter, agricultural residue, forestry residue, municipal solid waste, waste paper, pulp or paper mill residue (trees, shrubs, grasses, wheat, wheat straw, wheat midlings, sugar cane bagasse, corn, corn husks, corn kernel, corn fiber, municipal solid waste, waste paper, yard waste, branches, bushes, energy crops, fruits, fruit peels, flowers, grains, herbaceous crops, leaves, bark, needles, logs, roots, saplings, short rotation woody crops, switch grasses, vegetables, vines, sugar beet pulp, oat hulls, hard woods, wood chips, intermediate streams from pulping operations or soft woods (preferably trees, grasses, whole plants, or structural components of plants)) (all claimed).    ADVANTAGE - In the preparation of (I), essentially no carbon dioxide is produced in the biological conversion process; and only one mole of carbon dioxide is produced per mole of monosaccharide or monosaccharide unit in the material. The chemical energy efficiency of the method to produce the product from the material is greater than the chemical energy efficiency of a solely biological conversion process to produce the product and is greater than the chemical energy efficiency of a process in which all of the material is initially subjected to a thermochemical conversion step as part of the process to produce (I). The chemical energy efficiency of the method is at least 60 (preferably at least 82)%. In the process, at least 70% (preferably 100%) of carbohydrate substances in the material is converted into (I). The process efficiently converts carbon-containing materials such as biomass, into products in such a manner that the energy, carbon and mass content of the materials are efficiently transferred into such products. The process is economical.    DETAILED DESCRIPTION - Preparation of a product (I) from a material (II) comprising carbon-containing compounds (A), where less than 75 wt.% of (A) are carbohydrate substances, comprises: converting (II) into at least two intermediates, where at least one intermediate is produced by a biological conversion process and at least one intermediate is produced by a thermochemical conversion process, and reacting at least one biological process-produced intermediate and at least one thermochemical process-produced intermediate to form (I), where the chemical energy efficiency of the method to produce the product from the material is greater than the chemical energy efficiency of a solely biological conversion process to produce the product and is greater than the chemical energy efficiency of a process in which all of the material is initially subjected to a thermochemical conversion step as part of the process to produce (I). INDEPENDENT CLAIMS are included for methods of producing ethanol, propanol, propylene glycol, butanol and ethanol, and propanol and ethanol from (II).