This book presents techniques for designing fast, energy-efficient and timing predictable memory systems. By using a careful combination of compiler optimizations and architectural improvements, we can achieve more than what would be feasible at one of the levels in isolation. The described optimization algorithms achieve the goals of high performance and low energy consumption. In addition to these benefits, the use of scratchpad memories significantly improves the timing predictability of the entire system, leading to tighter worst case execution time bounds (WCET).