NOVELTY - Degrading a cellulosic material, comprises treating the cellulosic material with an enzyme composition in the presence of a glycoside hydrolases 61 (GH61) polypeptide having cellulolytic enhancing activity.    USE - The method are useful for degrading a cellulosic material for producing a fermentation product including an alcohol, an organic acid, a ketone, an amino acid, an alkane, a cycloalkane, an alkene, isoprene, polyketide, or a gas (all claimed).    ADVANTAGE - The enzyme composition increases efficiency, and provides cost-effective enzyme solutions for saccharification of cellulosic material.    DETAILED DESCRIPTION - Degrading a cellulosic material, comprises treating the cellulosic material with an enzyme composition in the presence of a glycoside hydrolases 61 (GH61) polypeptide having cellulolytic enhancing activity comprising (a) a GH61 polypeptide having at least 80% sequence identity to the mature polypeptide of SEQ ID NO: 2 or SEQ ID NO: 4, or at least 93% sequence identity to the mature polypeptide of SEQ ID NO: 6, (b) a GH61 polypeptide encoded by a polynucleotide that hybridizes under at least very high stringency conditions with (i) the mature polypeptide coding sequence of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 7, SEQ ID NO: 8, or SEQ ID NO: 9, (ii) the complementary DNA (cDNA) sequence of SEQ ID NO: 1 or SEQ ID NO: 3, or (iii) the full-length complement of (i) or (ii), (c) a GH61 polypeptide encoded by a polynucleotide having at least 80% sequence identity to the mature polypeptide coding sequence of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 7, or SEQ ID NO: 8, or the cDNA sequence of SEQ ID NO: 1 or SEQ ID NO: 3, or at least 93% sequence identity to the mature polypeptide coding sequence of SEQ ID NO: 5 or SEQ ID NO: 9, (d) a variant of the mature polypeptide of SEQ ID NO: 2, SEQ ID NO: 4, or SEQ ID NO: 6 comprising a substitution, deletion, and/or insertion at one or more positions and (e) a fragment of the GH61 polypeptide of (a), (b), (c), or (d) that has cellulolytic enhancing activity (where sequences not defined here may be found at ftp://ftp.wipo.int/pub/published-pct-sequences/publication). INDEPENDENT CLAIMS are included for:    (1) producing a fermentation product, comprising (a) saccharifying a cellulosic material with an enzyme composition in the presence of the GH61 polypeptide, (b) fermenting the saccharified cellulosic material with one or more fermenting microorganisms to produce the fermentation product, and (c) recovering the fermentation product from the fermentation;    (2) fermenting the cellulosic material, comprising fermenting the cellulosic material with the fermenting microorganisms, where the cellulosic material is saccharified with an enzyme composition in the presence of the GH61 polypeptide;    (3) a composition comprising the GH61 polypeptide; and    (4) a whole broth formulation or cell culture composition comprising the GH61 polypeptide.