The use of Fresnel lenses is expanding rapidly and they are now found in highly sophisticated optical systems. Their use has helped to solve many difficult optical problems but has also introduced some new design considerations. This paper will explain some of the advantages as well as some of the limitations of Fresnel lenses. "Special" optical design problems related to Fresnels will be discussed briefly. A description of tooling and part manufacturing methods and their related tolerances will be covered. Examples of existing Fresnel and "hybrid" systems will be given. On-going improvements and future developments that will make the use of Fresnels even more widespread will be described.© (1979) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.