Differential interference contrast (DIC) light microscopy is a technique which produces impressive 3D-like images of unstained specimens. The shadowing effects of the technique are remarkable, yet often misunderstood. The additional components required to enable DIC observation on a research-level microscope are precision made and expensive, so DIC is often overlooked in favour of the more common phase contrast technique. This article provides an overview of DIC microscopy, including guidelines for setting up the system correctly.