The principles and practices of object-oriented software construction have evolved since the 1960s. Object-oriented programming (OOP) is preoccupied with the manipulation of software objects. OOP is a way of thinking about problem solving and a method of software organization and construction.

The concepts and ideas associated with object-oriented programming originated in Norway in the 1960s. A programming language called Simula developed by Christian Nygaard and his associates at the University of Oslo is considered the first object-oriented language. This language inspired significant thinking and development work at Xerox PARC (Palo Alto Research Center) in the 1970s that eventually led to the simple, rich, and powerful Smalltalk-80 programming language and environment (released in 1980). Smalltalk, perhaps more than any programming language before or after it, laid the foundation for object-oriented thinking and software construction. Smalltalk is considered a “pure” object-oriented language. Actions can be invoked only through objects or classes (a class can be considered an object in Smalltalk). The simple idea of sending messages to objects and using this as the basis for software organization is directly attributable to Smalltalk.

Seminal work on object-oriented programming was done in the mid-1980s in connection with the Eiffel language. Bertrand Meyer in his classic book Object-Oriented Software Construction (Prentice-Hall, 1988; Second Edition, 1997) set forth subtle principles associated with OOP that are still viable and alive today.