The document summarizes Chapter 12 of the book "Big Java" which discusses object-oriented design. It covers the software development life cycle and design methodologies like the waterfall model, spiral model and extreme programming. It then explains how to perform object-oriented design through class discovery using CRC cards, identifying class relationships and documenting classes using UML diagrams and javadoc comments. As an example, it walks through applying these techniques to design a program to print invoices.