The range of applications of micro Computed Tomography (microCT) and the number of systems operating worldwide have expanded enormously over the last decade. This course provides attendees with a working knowledge of microCT and emphasizes practical examples. The course concentrates on x-ray absorption-based techniques but also covers phase contrast modalities. After introducing the physics behind the imaging methods, the mathematics of tomographic reconstruction and microCT apparatus designs are described at the qualitative, conceptual level required to understand the trade-offs in the experimental designs of the exemplar studies. Examples taken from diverse scientific and engineering fields illustrate data analysis and visualization strategies and include studies of: • Crack opening as a function of 3D position and applied load • Amount and spatial distribution of different phases - Calcification of heart valves - Metal matrix composites - Fluid distributions in porous solids - Interpretation of linear attenuation coefficients • Geometric characteristics of microstructures - Channels in chemical vapor infiltrated ceramic composites - Spongy or trabecular bone - Blood vessel networks A thread throughout is how improved instrumentation affects the ways investigators think about their characterization problems. The examples are also used to suggest promising directions for future studies.