A book, "Design Patterns: elements of reusable object-oriented software " by Gamma, Helm, Johnson and Vlissides , also known as the Gang of Four, or GoF. The first widely used source of software design patterns.
GoF describes patterns in a number of categories:
Creational Patterns
Structural Patterns
Behavioral Patterns
- Chain of Responsibility
- Command
- Interpreter
- Iterator
- Mediator
- Memento
- Observer
- State
- Strategy
- Template Method
- Visitor
For information about design patterns in general, see the design pattern article.