Abstract Essentials of Light Microscopy gives anyone new to microscopy sufficient information to understand how a light microscope works and how to set it up properly according to the principles of Köhler illumination, in order to acquire high-quality images. A microscope must provide resolution with sufficient contrast and magnification for the image to be visible. The different types of compound light microscope and stereo-microscopes are described. An image is formed when light interacts with matter. The theory of contrast-enhancement with transmitted light, reflected light, polarised light and fluorescent light is described and clearly explained. Advice is given on how confocal optical sectioning microscopes work, and how to use deconvolution to obtain blur-free fluorescent images. Other techniques, such as multi-photon, lightsheet, super-resolution and TIRF microscopy are described, as are live-cell imaging and colocalisation. The final two chapters describe recording digital images and basic optics. The aim of this book is not only to educate the reader in how to operate a light microscope, but also to enable them to work with core imaging facility staff to acquire high-quality scientifically rigorous images. The book concludes with appendices on maintenance, cleaning and care of the microscope and a brief historical outline.