Marker assisted selection or marker aided selection (MAS) is an indirect selection process where selection of a trait is based on marker (morphological, biochemical or DNA/RNA variation) linked to the trait (e.g. productivity, disease resistance, abiotic stress tolerance, and quality). In this aspect MAS can accelerate genetic improvement by increasing the accuracy of selection as well as reducing the time needed for selection. The present monograph explores the current status, application and future prospects on MAS.