Using as a point of departure previous work in marketing on optimal concept selection that utilizes product attribute-based customer preference and product cost models, the authors consider the concept selection stage of a new product development process. They offer empirical support for the need to push beyond these models to more complete “customer-ready” prototypes before choosing a concept to commercialize. Although the correlations between attribute-based predictions, on the one hand, and customer acceptance and product costs, on the other hand, are significant and substantial, too much variance is left unexplained to rely on these models in isolation. This implies that more detailed design work should be performed on several concepts in parallel. The authors also provide an integrated approach for concept generation and selection that leverages the unique strengths of marketing, design, and manufacturing in developing successful products.