Small-angle x-ray scattering is introduced as a method to measure the specific surface of paper. Changes in specific surface may be interpreted in terms of fiber bonding, both interand intra-fiber bonding. Although indistinguishable, both interand intra-fiber bonding contribute to increases in tensile modulus of paper. Differences in the specific surface that result from difference in drying, hemicellulose content, and beating were investigated. This x-ray scattering technique can provide a measure of the bonding energy density of the surface for use in characterizing the bonding efficiency of different pulps. Correlations between x-ray scattering and light scattering are pointed out. Initial measurements of tensile modulus and specific surface are consistent with a model in which hydrogen bonds are the functional structural units in a bonded sheet. -- AATA