In this book, an attempt is made to address some of the remaining technical challenges of the phase change optical recording such as higher data storage capacity at lower $/Mb, higher speed data transfer and prolonged thermal & chemical stability of written marks over long usages. The first part of the book provide an insight into the intense development efforts that resulted in an optimized material composition (Sb100-x-ySnxIny)P(ZnS-SiO2)Q that is used as the parent recording material to develop Blu-ray Recordable (BDR) L2H discs that meet the current standard specifications but could be mass produced at significantly lower costs.Second part of the book illustrates the work related to the addition of indium into (SbxTe1-x)y Ge1-y matrix for improving the crystallization speed of Sb69Te31 composition that led to the successful discovery of a new 1X-2.5X BDRE format (current specification is 1X-2X only). The third part of the book lists the successful attempts to improve the archival life of CDRW media format with the introduction of an optimized concentration of N2 as a dopant during the course of sputtering of phase change layer.