The document discusses structural models, class diagrams, and the process of creating CRC cards and class diagrams. It provides definitions of key concepts like classes, attributes, operations, and relationships. It describes the elements of class diagrams including classes, attributes, operations, multiplicities, and how to simplify complex diagrams. It outlines a 7 step process for creating CRC cards and class diagrams including identifying objects, role-playing CRC cards, and reviewing the models.