This chapter provides a reference on aPrioi’s Cost Scripting Language (CSL). The code in a CSL module specifies the rules and formulas that make up a particular portion of a cost model (such as the portion that computes a cost taxonomy for a particular process). So experienced users can employ CSL to implement and customize the details of cost model logic. For more information on working with cost model logic, see also Working with Cost Model Logic. For information on working with cost model data, see Working with Cost Model Data and Metadata.