In order to maintain the highest standards of treatment, proper control of operating field is mandatory. This is even more important in present times when most procedures require adhesion/bonding which require total isolation to be successful. Isolation of the working field enhances both quantity and quality of restorative and endodontic treatment. For any clinical situation, appropriate technique should be selected to maintain a clear working area. A thorough knowledge of the preliminary procedures addressed in this chapter affords maximum comfort for the patient while reducing physical strain on the dental team. Maintaining optimal moisture control is a necessary component in the delivery of high-quality restorative and endodontic treatment.