Harmful iterations increase product development project lead time and make their scheduling difficult. On the other hand, iteration is not always undesired; some iteration is natural to product development and feedback providing iteration in the early phases of development may increase development speed. In this book causes for harmful iterations in product development are recognized and classified, their impacts are diagnosed, and means to diminish their impacts are developed. Also, an iterative development model aiming at early, feedback providing iterations for avoiding later harmful iterations is presented.