The following outline is provided as an overview of and topical guide to human–computer interaction: Human–Computer Interaction (HCI) – the intersection of computer science and behavioral sciences — this field involves the study, planning, and design of the interaction between people (users) and computers. Attention to human-machine interaction is important, because poorly designed human-machine interfaces can lead to many unexpected problems. A classic example of this is the Three Mile Island accident where investigations concluded that the design of the human-machine interface was at least partially responsible for the disaster. What type of thing is human–computer interaction? Human–Computer Interaction can be described as all of the following: A field of science – systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe. An applied science – field that applies human knowledge to build or design useful things. A field of computer science – scientific and practical approach to computation and its applications. An application of engineering – science, skill, and profession of acquiring and applying scientific, economic, social, and practical knowledge, to design and also build structures, machines, devices, systems, materials and processes. An application of software engineering – application of a systematic, disciplined, quantifiable approach to the design, development, operation, and maintenance of software, and the study of these approaches; that is, the application of engineering to software. A subfield of computer programming – process of designing, writing, testing, debugging, and maintaining the source code of computer programs. This source code is written in one or more programming languages (such as Java, C++, C#, Python, PHP etc.). The purpose of programming is to create a set of instructions that computers use to perform specific operations or to exhibit desired behaviors. A social science – academic discipline concerned with society and human behavior. A behavioral science – discipline that explores the activities of and interactions among organisms. It involves the systematic analysis and investigation of human and animal behavior through controlled and naturalistic observation, and disciplined scientific experimentation. Examples of behavioral sciences include psychology, psychobiology, and cognitive science. A type of system – set of interacting or interdependent components forming an integrated whole or a set of elements (often called 'components' ) and relationships which are different from relationships of the set or its elements to other elements or sets. A system that includes software – software is a collection of computer