A vital part of a dental practitioner's arsenal in the dental operatory is an awareness and understanding of the LCU used, along with its limitations. LCUs play a critical role in the longevity of a restoration, all else being equal. By being aware of the LCU used in the dental operatory along with its specific limitations, a clinician may ensure a better match between the LCU, and restorative material placed. This book describes the various types of LCUs available in market today along with the different curing techniques used for composite resin build up. A brief discussion about its advantages, limitation and factors affecting the curing are also included whilst discussing about the optical hazards, infection control and maintenance of LCUs.