Human-centered design (HCD) [also Human-centred design, as used in ISO standards] is an approach to problem solving, commonly used in design and management frameworks that develops solutions to problems by involving the human perspective in all steps of the problem-solving process. Human involvement typically takes place in observing the problem within context, brainstorming, conceptualizing, developing, and implementing the solution.
Human-centred design is an approach to interactive systems development that aims to make systems usable and useful by focusing on the users, their needs and requirements, and by applying human factors/ergonomics, usability knowledge, and techniques. This approach enhances effectiveness and efficiency, improves human well-being, user satisfaction, accessibility and sustainability; and counteracts possible adverse effects of use on human health, safety and performance. ISO 9241-210:2010(E)
Human-centered design builds upon participatory action research by moving beyond participants' involvement and producing solutions to problems rather than solely documenting them. Initial stages usually revolve around immersion, observing, and contextual framing in which innovators immerse themselves with the problem and community. Consequent stages may then focus on community brainstorming, modeling and prototyping, and implementation in community spaces. Further, human-centered design typically focuses on integrating technology or other useful tools in order to alleviate problems, especially around issues of health. Once the solution is integrated, human-centered design usually employ system usability scales and community feedback in order to determine the success of the solution.
In Architect or Bee?, Mike Cooley coined the term "human-centred systems" in the context of the transition in his profession from traditional drafting at a drawing board to computer-aided design. Human-centred systems, as used in economics, computing and design, aim to preserve or enhance human skills, in both manual and office work, in environments in which technology tends to undermine the skills that people use in their work.
See in particular; Human-centred systems by Mike Cooley; Chapter 10; Designing Human-centred Technology: A Cross-disciplinary Project in Computer-aided Manufacturing; Springer-Verlag London 1989; Editor: Howard Rosenbrock; ISBN978-3-540-19567-2
In the 2008 paper "On Human-Machine Symbiosis" Cooley asserts "Human centredness asserts firstly, that we must always put people before machines, however complex or elegant that machine might be, and, secondly, it marvels and delights at the ability and ingenuity of human beings. The Human Centred Systems movement looks sensitively at these forms of science and technology which meet our cultural, historical and societal requirements, and seeks to develop more appropriate forms of technology to meet our long-term aspirations. In the Human Centred System, there exists a symbiotic relation between the human and the machine in which the human being would handle the qualitative subjective judgements and the machine the quantitative elements. It involves a radical redesign of the interface technologies and at a philosophical level the objective is to provide tools (in the Heidegger sense) which would support human skill and ingenuity rather than machines which would objectivise that knowledge". 
Using a human-centered approach to design and development has substantial economic and social benefits for users, employers and suppliers. Highly usable systems and products tend to be more successful both
technically and commercially. In some areas, such as consumer products, purchasers will pay a premium for well-designed products and systems. Support and help-desk costs are reduced when users can understand
and use products without additional assistance. In most countries, employers and suppliers have legal obligations to protect users from risks to their health, and safety and human-centered methods can reduce these risks (e.g. musculoskeletal risks). Systems designed using human-centered methods improve quality, for example, by:
increasing the productivity of users and the operational efficiency of organizations;
being easier to understand and use, thus reducing training and support costs;
increasing usability for people with a wider range of capabilities and thus increasing accessibility;
improving user experience;
reducing discomfort and stress;
providing a competitive advantage, for example by improving brand image;
contributing towards sustainability objectives
Human-centered design may be utilized in multiple fields, including sociological sciences and technology. It has been noted for its ability to consider human dignity, access, and ability roles when developing solutions. Because of this, human-centered design may more fully incorporate culturally sound, human-informed, and appropriate solutions to problems in a variety of fields rather than solely product and technology-based fields. Typically, human-centered design is more focused on "methodologies and techniques for interacting with people in such a manner as to facilitate the detection of meanings, desires and needs, either by verbal or non-verbal means." In contrast, user-centered design is another approach and framework of processes which considers the human role in product use, but focuses largely on the production of interactive technology designed around the user's physical attributes rather than social problem solving.
The Stanford d.school at Stanford University is a large proponent of human-centered design and teaches innovative approaches to human problems by focusing on empathy-informed solutions.
Human-centered design has been both lauded and criticised for its ability to actively problem solve with affected communities. Criticisms include the inability of human-centered design to push the boundaries of available technology by solely tailoring to the demands of present-day solutions, rather than focus on possible future solutions. In addition, human-centered design often considers context, but does not offer tailored approaches for very specific groups of people. New research on innovative approaches include youth-centered health design, which focuses on youth as the central aspect with particular needs and limitations not always addressed by human-centered design approaches.
Whilst users are very important for some types of innovation (namely incremental innovation), focusing too much on the user may result in producing an outdated or no longer necessary product or service. This is because the insights that you achieve from studying the user today are insights that are related to the users of today and the environment she or he lives in today. If your solution will be available only two or three years from now, your user may have developed new preferences, wants and needs by then.