The text contains a detailed and current presentation of the program analyses and transformations that extract the flow of data in computer memory systems. The emphasis is on a framework for the optimization of code for imperative programs and greater computer systems efficiency. In addition, the author shows that correctness of program transformations is guaranteed by the conservation of data flow. Professionals and researchers in software engineering, computer engineering, program design analysis, and compiler design will benefit from its presentation of data-flow methods and memory optimization of compilers.