Dental caries is one of the most common diseases of the oral cavity affecting both child and adult.Management of caries and its complication is the crux of dentistry. Every year thousands of rupees are being spent on restorations. With advent of fluorides there has been a reduction in the prevalence and a change in caries pattern. A small initial lesion often progresses under an intact layer of surface enamel. Early carious lesions are reversible and can be arrested. Non invasive intervention can convert a lesion from an active to an inactive state. Such small lesions are getting difficult to diagnose ,precise diagnostic methods are the need of the hour.To create opportunity for a preventive approach to the management of caries,it is important to keep abreast of developments in diagnostic systems. It is apparent that conventional methods for detection of dental caries do not fulfill the criteria for an ideal caries detection method. These methods rely on subjective interpretation and are insensitive to early caries detection. This book focuses light on both conventional and advance techniques for caries detection.