Ontology modeling lacks standard methodology and sufficient literatures. There are very few books available in the market place that talks about ontology modeling methodology and its application and almost none in the area of product and process design. Manufacturing enterprises are competing in an environment, which requires the ability to rapidly design their products and processes. This ability requires modeling methods to support design team in providing design information. The objective of this book is to illustrate the ontology modeling methodology, called as the Domain Knowledge Acquisition Process (DKAP) methodology and its application in product and process design. It is a well structured generic methodology and can be used to model any domain of interest. This book also presents a domain ontology model for generic product and process design that can serve as a source of design knowledge for enterprise engineering. A direct benefit of such ontology is the enhanced ability to perform product and process design. The goal of this book is to explain the ontology modeling techniques to more or less anybody involve with the knowledge management specially ontology modelers/authors and collaborative design teams.