Renes Descartes (1596-1650) was a man of many talents. He was a mathematician, scholar, traveler, physicist, philosopher and thinker. In his spare time he was a primary contributor to modern philosophy as well as analytic geometry. According to Descartes, the guide to truth is to doubt everything systematically until you arrive at a clear idea that is beyond all doubt (Flexner, 1995). This is sound advise for any enterprise software product. Every day believers surround us. We are passionate about our product and company and we can all benefit from taking a step back and forcing a harder look. Using Descartes philosophy, the preceding five chapters are brought together to form a systematic method to challenge a company’s product from the customer’s viewpoint.