Introductory technical guidance for professional engineers and construction managers interested in energy efficient data centers. Here is what is discussed: 1. INTRODUCTION, 2. INFORMATION TECHNOLOGY (IT) SYSTEMS, 3. ENVIRONMENTAL CONDITIONS, 4. AIR MANAGEMENT, 5. COOLING SYSTEMS, 6. ELECTRICAL SYSTEMS, 7. OTHER OPPORTUNITIES FOR ENERGY-EFFICIENT DESIGN, 8. DATA CENTER METRICS AND BENCHMARKING.