Design Patterns can be seen as repeatable solutions to common problems arising in software design. They provide a great, language-agnostic

way of talking about software architecture.

"Head First Design Patterns" explains simply:

knowledge of patterns you can start to apply them to your new designs

There are a number of benefits to considering using a design pattern:

- Helps your system prepare for accommodating change - an inevitability of software development

- Allows for a shared language when describing a system - you can "say more with less"

- Can lead to a better designed system (through *appropriate use* of a design pattern)

There are 23 'Gang of Four' patterns that are generally considered the foundation for all other patterns. They are categorised into three groups: Creational, Structural and Behavioural.

[SourceMaking](https://sourcemaking.com/design_patterns) highlights some of the criticisms of using design patterns:

- Targets the wrong problem

- Lacks formal foundations

- Leads to inefficient solutions

- Does not differ significantly from other abstractions

Some argue that design patterns ultimately boil down to good software design with careful consideration of SOLID principles.

[Jeff Atwood also has some thoughts on design patterns](http://blog.codinghorror.com/rethinking-design-patterns/)