During 20th Century, it was believed that any nation which could produce cheap and dependable products, systems, and services would eventually be the industrial leader of the world. This led to a technological and industrial race which involved indiscriminate use of the resources and overlooking the wastages involved. This industrial revolution resulted in severe environmental degradation of the planet we live in. With the passage of time, it is now realized that as the world resources become scarce and the human population rises, the cost of raw materials and resources is likely to escalate spirally. Naturally, to meet the demand of the rising population, the volume of production has to be increased, which will further aggravate the world environmental health unless strong pollution prevention measures are vigorously pursued and implemented.
In 1987, the United Nations released what is known as Brundtland Report , which emphasized the necessity of sustainable development and defined it as "development which meets the needs of the present without compromising the ability of future generations to meet their own needs".
The rate at which the environmental degradation is taking place due to over-exploitation of resources on one hand and their wastage on the other hand could lead humans to surpass the carrying capacity of Earth. Realizing the gravity of the situation, more than 1600 scientists, including 102 Noble laureates collectively signed a Warning to Humanity in 1992, which reads as follows:
"No more than one or few decades remain before the chance to avert the threats we confront, will be lost and the prospects for humanity immeasurably diminished... A new ethics is required- a new attitude towards discharging responsibility for caring for ourselves and for Earth ... this ethics must motivate a great movement, convincing reluctant leaders, reluctant governments and reluctant people themselves to affect the needed changes".
It had been abundantly emphasized  that the future prosperity of nations in 21st Century will depend upon their degree of concern for performance, environment and economic implications for industrial and technological advancement or what has been known as sustainable development.
Sustainability, in nutshell, can be defined as "meeting the needs of the present without compromising the ability of future generations to meet their own needs". Sustainability will give our children and future generations better chances to survive and lead a better life. The world population at present is 6.5 billion and is expected to grow to 9 billion by 2050. This increase would necessitate more materials and energy requirements. Materials which were once cheap would eventually become difficult to harness and costly in near future. Cost and availability are likely to further worsen with rapid growth in developing countries while they consume natural resources faster than these can be replenished or until their substitutes are found. Energy requirement is also likely to increase with increase in the number of consumers and also for manufacturing products. Since water is a life sustaining requirement, there is a threat to its availability as well as cost besides ensuring its purity and being clean. The fact that the resources are finite and should not be wasted, it becomes necessary to use them wisely and judiciously.
Therefore, to affect sustainability, the basic requirements are: dematerialization (or use of minimum material in all our requirements) and use of minimum energy besides minimizing any wastages (goal should be of zero waste) during the entire life cycle activities of products systems and services. In fact, zero waste is defined as ... "designing and managing products and processes to reduce the volume and toxicity of waste and materials, conserve and recover all resources, and not burn or bury them. Implementing Zero Waste will eventually eliminate all discharges to land, water or air that may become a threat to planetary, human, animal or plant health."
In Europe, Restriction on Hazardous Substances (ROHS) and Waste Electrical and Electronic Equipment (WEEE) directives are assisting the electronics and computer industries; and the newly enacted Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) directive will have an even more profound impact on sustainability initiatives. While, ROHS restricts the use of hazardous materials (such heavy metals such as lead, cadmium etc.) in the manufacture of electronic and electrical equipment, WEEE requires makers of electrical goods to collect, recycle and recover essential targets for their products at end of life. Concerned manufacturers need to develop a mechanism for reclaiming product from the consumer. Finally, REACH requires testing and registration of most chemicals manufactured in or imported into the EU. Producers and importers may be required to test and report the effects of particularly risky chemicals, and the most hazardous (carcinogens, reproductive toxins, or those that accumulate in humans or animals) can only be used if expressly authorized by the European Chemicals Agency. These wide ranging measures and directives will eventually affect all manufacturers and are expected to improve sustainability by substantial measure.
Realizing the importance foregoing factors, it was considered prudent to redefine performance criteria of products, systems and services through a parameter, which not only includes criteria like , quality, reliability, maintainability, safety (and/or security) but also sustainability. What is called as performability  is not restricted to mean dependability of a product, system or service alone but also its sustainability. The idea is that overall performance of products, systems and services must not only be judged by how good they perform their designed objective but also by how they are produced, maintained and used over their entire life cycle and finally disposed of (at the end of their intended service period). This naturally involves consideration of influence of the entire processes of production and the conditions of use of products, systems and services may have on the environment. We can also define Performability Engineering as a holistic interdisciplinary approach to optimally engineer dependable and sustainable products, systems and services.
With sustainability becoming a necessity in 21st Century, we can't but accord it a place of importance, particularly in the design of engineering products, systems and services to conserve material energy and to arrest environment pollution. Therefore, it is significant to mention here that our effort to extend the concept of performability to include sustainability as an additional design parameter besides dependability (quality, reliability, maintainability and safety) was a step in the right direction. In order to promote dissemination of this concept and research in this area an international journal was launched in 2005. The objective of launching the International Journal of Performability Engineering (or IJPE) was to bring to fore all the aspects of performance of any product, system and service in their totality. Another reason to launch this journal was to bring all the players of dependability and sustainability together on a common platform so that an interaction takes place between these diverse sections of researchers which otherwise were working in isolation and sometimes unaware of each others' work.
IJPE will keep on striving to present new ideas in this endeavor to achieve goal of producing sustainable products, systems, and services. To further highlight the scope of our efforts, a Handbook of Performability Engineering  was published with Springer in 2008. This Handbook covers all the aspects of performance attributes including sustainability in great details. We have also brought out special issues occasionally to encourage this interaction.
The benefits accruing from practicing the principles of sustainability are far-reaching and help increase the profitability and provide an edge in competition over other producers. It is soon going to become a part of business etiquette in the global economy. Use of fewer materials will definitely cut costs. Although switching to more sustainable materials may or may not reduce costs on the face of it, but is likely to reduce waste, emissions and pollution, and may avoid shortages or price increases for the less-sustainable material. Use of less energy in the production process lowers overheads and product costs, which can provide more money for an enterprise to invest in R&D, upgrading plant or equipment or capital improvements, all of which can contribute to the long-term success for the company. Use of renewable sources of energy is going to be in use eventually to offer the advantage of clean energy. For example solar energy is available for free and is sustainable for millions of years. Burning fossil fuel for energy requirement is not really sustainable as it took millions of years to produce oil, coal, and gas but humans are going to burn or exhaust fossil fuels reserve within a few generations. There are other sources of renewable energy as well. Wise use of natural resources and taking steps to lower their environmental impact will help in attracting and retaining customers who are willing to pay more for safe, healthy, and green products. In fact, sustainability challenges are also spurring the need for new technological solutions. Manufacturers who can add or extend an existing product line to meet the challenges have huge market opportunity. Also resorting to fast, cost-effective remanufacturing by using only standard, interchangeable parts may help boost the business opportunities. Smart business leaders will build sustainability into their business models. In addition to the environmental benefits, sustainability offers great financial, competitive and other business rewards that give manufacturers a competitive edge in a global market.
Sustainability today is a very complex term that can be applied to many diverse facets of life on Earth, and is used as an umbrella term to measure and calculate the outcome all of human activities, including biological entities such as: wetlands, prairies and forests and is also expressed in Human organization concepts, such as: eco-villages, eco-municipalities, sustainable cities and towns, sustainable communities, and human activities and disciplines, such as: sustainable agriculture, sustainable architecture and buildings using renewable energy. Sustainability is also defined as the ability of an ecosystem to maintain ecological processes, functions, and to preserve biodiversity and productivity into the future. Earth needs biodiversity and humans need biodiversity to survive on Earth. Food security is needed to assure affordable price to weaker section of human population. For example, prices of corn and other cereals have risen which affects the people whose food is based on these cereals and some possibly cannot afford to buy. In essence, the idea is to use Earth's resources at a rate at which they can be replenished if humanity is to live sustainably. If we cannot bring back the pristine environment of Earth, we should at least attempt to arrest its further degradation using all the means available at our command.
Surely, sustainability can be achieved: by reducing consumption of resources -such as water and energy, through better building practices to reduce energy waste, using more fuel efficient engines in cars and trucks etc.to reduce air pollution, increasing recycling - using recycled materials, preserving forest cover of Earth, conserving top soil of land area etc., preserving water sources and marine life and lastly living a sustainable life style.
It may be difficult to change lifestyle but at least the measures which improve sustainability must be given a good chance. For example, use of bicycle over the use of cars for short distances or use of pooled cars for going to office if possible or make use of public transport. Food habits also need to reorient. It should be good idea to be green consumer while shopping. We should try to become carbon-neutral. There are very many things that can be done to promote sustainability and sustainable life style. This is of course not the place to discuss them all but it would be necessary to mention these at least.
Therefore, when I received a proposal from the Guest Editors to bring out a special issue of International Journal of Performability Engineering, I readily accepted the idea and the Guest Editors worked over time to realize this project. This special issue on Balancing Technology, Environment and Lifestyles is an effort in this direction. In fact, the highlights of this year's IJPE issues will be two special issues planned on sustainability, viz., the present issue on Balancing Technology, Environment and Lifestyles, and the other on Design of Products, Systems and Services for Dependability and Sustainability.
There was one more reason to support this idea of bringing out this special issue, which is the issue comprises the papers mainly written by budding researchers and students from Europe, mostly those who are doing Ph.D. under the guidance of their professors and are keen to propagate the concept of sustainability. This is an important and positive step in promoting sustainability as this way it would become a subject of curricula and research in universities and educational institutions.
I am informed that these papers which are extended versions of the papers that were presented at a symposium which was organized, managed and conducted entirely by these budding researchers without any financial support from any organization or institution. I feel they must be given due credit for undertaking such an onerous task. This symposium was a part of a series of annual events which aim to bring together young researchers from a broad spectrum of disciplinary backgrounds interested in the major challenges posed by achieving Sustainable Development. The first such symposium was held at the Trinity College (TCD) in Dublin in February 2011.The second was held in Austria by the Institute for Process and Particle Engineering at the Graz University of Technology, in February 2012. The third edition took place from 13th to 15th February, 2013 at Parthenope University of Naples, Italy and the fourth symposium took place from 19th to 21th February, 2014 at Pan-European University of Bratislava. These Symposia provide postgraduate researchers from European universities, especially Ph.D. Students, an opportunity to present their work on various aspects of sustainability.
The moving force behind the present issue is Ms. Maddalena Ripa who is a Ph. D. Student in the Department of Sciences for the Environment at Parthenope University of Napoli of Italy and the task was handled under the apt guidance of two well-known Professors in the area, namely, Professor Sergio Ulgiati of Department of Sciences for the Environment at the Parthenope University of Napoli, Italy, and Professor Hans Schnitzer of Process Engineering at the Technische Universit?t Graz, Austria. This trio deserves all the credit for successful publication of this issue. All papers included in this issue were reviewed at least by two referees and comments received were incorporated during the revision of the papers by the authors. I would be failing in my duty as an Editor-in-Chief of this journal, if I do not acknowledge the uninhibited support of reviewers and referees including the two professors mentioned above who helped maintain high standards of publication of this journal.
I would like to assure IJPE readers that they will find this special issue quite refereshing and educative. We will continue to present various aspects of performability engineering and new research to our readers through this journal in the years to come.
 United Nations. Report of the World Commission on Environment and Development. General Assembly Resolution 42/187, 11 December 1987.
 Misra, K. B (Ed.). Clean Production : Environnemental and Economic Persperctives. Springer Verlag, Berlin, 1996.
 Misra, Krishna B. Editorial. International Journal of Performability Engineering, 2005 1(1):1-3.
 Misra, Krishna B (Ed.). Handbook of Performability Engineering. Springer Verlag. London, 2008.