Patterns is a empirical solution to a problem that is defined through successful exprience and example in real systems. The most famous book about patterns is 'Design patterns, popularised by the seminal Design Patterns: Elements of Reusable Object-Oriented Software by Gamma, Helm, Johnson and Vlissides'. The four authors are also known as the Gang of Four. Get the book if you don't already have it. Having a good knowledge of the existing design patterns will help you recognize structures and accelerate the speed of your system design or development.