PURPOSE/OBJECTIVE It is important to consider the fundamental definition of trend@ which for this book is defined as the general direction in which something tends to move. The trends referenced or presented in this book should not be taken literally but rather considered as a general indication of both the direction and the magnitude of the subject matter. The intended audience for this document includes. ? planners and managers of datacom facilities@ ? facility design teams planning and designing datacom facilities@ and ? facility architects and engineers who require insight on datacom equipment energy density and installation planning trends. The variety of backgrounds and educational and practical experience among the intended audience can result in many different methods used to apply the information in this book. Fortunately@ the book is designed for these multiple methods with the understanding that any methodology employed focuses on the concept of growth patterns. Some practical examples of ways the growth patterns can be extracted are provided in this book@ but there are additional methods that can be considered in the planning@ design@ and operation of a datacom facility. The growth patterns can use any baseline and provide a mathematical road map to the future. The baseline can use any metrics or units that make the most sense for the reader. For example@ the units can be dimensionless@ ? density centric (e.g.@ W/ft2 [W/m2])@ or ? interface centric (e.g.@ kW ack or kW/cabinet). It is important for the information technology (IT) and facilities industries to have a general understanding of areas that are not directly their responsibility but do directly impact their budgets@ operation@ or performance. This same general understanding is important for equipment manufacturers@ design architects/engineers@ contractors@ and service technicians.