Book excerpt: Contains the proceedings of the conference Multi-Scale and High-Contrast PDE: From Modelling, to Mathematical Analysis, to Inversion, held June, 2011. The volume focuses on recent progress towards a complete understanding of the direct problem with high contrast or high frequencies, and unified approaches to the inverse and imaging problems for both small and large contrast or frequencies. It also includes contributions on the inverse problem, both on its analysis and on numerical reconstructions.