Progressive function points was derived for greater accuracy in the estimation of Function Point Analysis which is used for size estimation of IT Projects. The new improvements are based on the actual Function point count based on elementary inputs, outputs and integrated process flows within the respective functions. Progressive function points are better suited for application that may have the following characteristics Projects with complex business rules and multiple workflows. Complex operations other than standard CRUD functionality. Integration of Reuse within functions. Greater Accuracy of Cost & Schedule Index. Greater Clarity and Accountability into costing of applications. Passing external reviews such as CPMG Audits. Integration of new languages and programming tools. Progressive Function Point Analysis was developed for mitigating problems in the implementation of FPA in agile projects. The estimation principle addresses the concerns with regard to effort and accurate sizing in projects. These ideas were implemented through various tools and an open source worksheet was built on the new principles to address many concerns such as Accuracy, Reuse, Workflow Estimation. Some practice specific enhancements and applications have also been discussed where the standard model is not applicable. This book is focused on training Architects and Project Managers in Progressive Estimation technique, for seasoned FPA Analyst, we provide new tools and methods to estimate the effort and revalidate their current estimates by using our free and open source tools, which also provides both cost and schedule index and advanced customizable workbooks . By providing Progressive FPA estimates, the cost and effort are justified and can be validated against the actual work.