The phenomenon of structural branching is ubiquitous in a wide array of materials: polymers, ceramic aggregates, polymeric networks, and gels. Branching has a strong influence on the structure-property relationships of these materials. Despite the interdisciplinary importance and decades of effort, the analytical description and quantification of branching are weak. Existing techniques for polymers based on size exclusion chromatography and rheology are, at best, qualitative, and quantitative characterization techniques such as nuclear magnetic resonance spectroscopy and transmission electron microscopy (for ceramic aggregates) have limitations in providing routine quantification. For ceramic aggregates, theoretical work has dominated, and only a few publications on analytical studies exist to support the theory. Small-angle scattering of X-rays and neutrons can be used to quantify the branch content through application of concepts native to fractal geometry. (c) 2006 Wiley Periodicals, Inc.