NOVELTY - Isolated polypeptide having cellulolytic enhancing activity, comprising e.g. (a) a polypeptide having sequence identity to the mature polypeptide of SEQ ID NO: 2, 4, or 6, (b) a polypeptide encoded by a polynucleotide that hybridizes under high stringency conditions with the mature polypeptide coding sequence of SEQ ID NO: 1 or, the mature polypeptide coding sequence of SEQ ID NO: 3, or 5, is new, where the sequences not defined here may be found at ftp://ftp.wipo.int/pub/published-pct-sequences/publication.    USE - The isolated polypeptide is useful for degrading a cellulosic material and fermenting the cellulosic material to produce a fermentation product (all claimed) such as fuel (ethanol, n-butanol, isobutanol, biodiesel and jet fuel) and platform chemicals (e.g. acids, alcohols, ketones, gases and oils), where ethanol is useful as drinking ethanol (i.e. potable neutral spirits), and industrial ethanol.    ADVANTAGE - The isolated polypeptide exhibits enhanced cellulolytic activity, thus ensuring efficient and cost-effective saccharification of the cellulosic material.    DETAILED DESCRIPTION - Isolated polypeptide having cellulolytic enhancing activity, comprising (a) a polypeptide having at least 65% sequence identity to the mature polypeptide of SEQ ID NO: 2, at least 70% sequence identity to the mature polypeptide of SEQ ID NO: 4, or at least 75% sequence identity to the mature polypeptide of SEQ ID NO: 6, (b) a polypeptide encoded by a polynucleotide that hybridizes under at least high stringency conditions with the mature polypeptide coding sequence of SEQ ID NO: 1 or its cDNA sequence, the mature polypeptide coding sequence of SEQ ID NO: 3 or its cDNA sequence, or the mature polypeptide coding sequence of SEQ ID NO: 5 or its full-length complement, (c) a polypeptide encoded by a polynucleotide having at least 65% sequence identity to the mature polypeptide coding sequence of SEQ ID NO: 1 or its cDNA sequence, at least 70% sequence identity to the mature polypeptide coding sequence of SEQ ID NO: 3 or its cDNA sequence, or at least 75% sequence identity to the mature polypeptide coding sequence of SEQ ID NO: 5, (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 polypeptide of (a)-(d) that has cellulolytic enhancing activity, is new, where the sequences not defined here may be found at ftp://ftp.wipo.int/pub/published-pct-sequences/publication. INDEPENDENT CLAIMS are included for:    (1) an isolated polynucleotide encoding the polypeptide;    (2) a nucleic acid construct or expression vector comprising the polynucleotide linked to one or more control sequences that direct the production of the polypeptide in an expression host;    (3) a recombinant host cell comprising the polynucleotide linked to the control sequences;    (4) preparations of the polypeptide;    (5) a transgenic plant, plant part or plant cell transformed with a polynucleotide encoding the polypeptide;    (6) producing a mutant of a parent cell, comprising inactivating a polynucleotide encoding the polypeptide, which results in the mutant producing less of the polypeptide than the parent cell;    (7) a double-stranded inhibitory RNA (dsRNA) molecule comprising a subsequence of the polynucleotide, where optionally the dsRNA is an small interfering RNA (siRNA) or an microRNA (miRNA) molecule;    (8) an isolated polynucleotide encoding a signal peptide comprising amino acids 1-19 of SEQ ID NO: 2, amino acids 1-19 of SEQ ID NO: 4, or amino acids 1-18 of SEQ ID NO: 6;    (9) producing a protein, comprising cultivating a recombinant host cell comprising a gene encoding a protein operably linked to the polynucleotide, where the gene is foreign to the polynucleotide encoding the signal peptide, under conditions conducive for production of the protein;    (10) a process-I for degrading a cellulosic material, comprising treating the cellulosic material with an enzyme composition in the presence of the polypeptide;    (11) a process-II for producing a fermentation product, comprising (a) saccharifying the cellulosic material with the enzyme composition in the presence of the 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;    (12) fermenting a cellulosic material, comprising fermenting the cellulosic material with the fermenting microorganisms, where the cellulosic material is saccharified with the enzyme composition in the presence of the polypeptide; and    (13) a whole broth formulation or cell culture composition comprising the polypeptide.