The Performance Metrics for Intelligent Systems (Per- MIS 2006) workshop was held during August 21-23, 2006 at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland, USA. The PerMIS series (the current workshop is the sixth) is targeted at defining measures and methodologies of evaluating performance of intelligent systems. PerMIS 2006 focused on applications of performance measures to practical problems in commercial, industrial, homeland security, and military applications. An important element of overall performance evaluation is that of assessing the technical maturity of a given technology or system. One approach for accomplishing this is known as Technology Readiness Level (TRL) assesment. TRL evaluations have been the focus of past PerMIS workshops and continue to be a foundational theme. This paper will provide an overview of the workshop and various topics that are closely related to the theme of the AIPR workshop.