Understanding the management of organic matter accumulation in turfgrass systems is complex and often contradictory.   Many factors influence organic matter accumulation, including grass type, rate of plant growth and decay, soil chemical and physical properties, biological activity, cultural practices and environmental conditions. In turfgrass installations, organic matter may be a predominantly organic thatch layer in a Kentucky bluegrass home lawn to a mixture of organic matter, sand and biological byproducts in a well managed golf putting green. As is typical of most biologically based systems it is difficult to simplify the dynamic, diverse and multifaceted condition of OM accumulation in turfgrass. The chapter in the third edition of the ASA Turfgrass monograph should be used chapter as a guide to a better understanding of the body of literature on the topic and if so inclined, pursue  research endeavors to fill the voids in understanding OM accumulation in turfgrass or, if a turfgrass practitioner,  use the information as an aid in developing management strategies.