The authors of this book are called the "gang of 4". Many say that they were the ones to initially define the design patterns that are used today. Most books written today on design patterns stem from the gang of 4 and this book. It is a good read.
Elements of Reusable Object-Oriented Software
by Erich Gamma, Richard Helm, Ralph Johnson, John Vlissides
Addison-Wesley Pub Co; 1st edition (January 15, 1995)
You can purchase the book at this site: