Atomic scale defects play a key role in determining the mechanical and physical properties of material systems. In metals and alloys, defects such as dislocations control deformation and failure behaviour; in semiconductor devices they can be detrimental to electrical performance. Transmission electron microscopy (TEM) transformed our ability to understand and better control atomic scale defects by allowing us to image and probe them. However, it is limited to thin samples, which may not be representative of behaviour in the bulk. To complement TEM, we use a variety of X-ray techniques to measure the lattice distortions associated with atomic scale defects. As a first step, we recently demonstrated that, using micro-beam Laue diffraction, we can measure the elastic strain fields associated with a single dislocation!