Moire interferometry provides contour maps of in-plane displacement fields with high sensitivity and high spatial resolution. It has matured rapidly as an invaluable tool for engineering analyses, proved by many industrial and scientific applications. With the typical reference grating frequency of 2400 lines/mm, the contour interval is 0.417 μm displacement per fringe order. For microscopic moire interferometry, sensitivity corresponding to 17 nm per contour has been achieved. Reliable normal strains and shear strains are extracted from the displacement data for bodies under mechanical, thermal and hydrostatic loading. The characteristics and basic concepts of moire interferometry are reviewed. Significant examples from the fields of composite materials, fracture mechanics, electronic packaging and biomechanics are presented.