Virtual libraries are the new vision of libraries of the future. They are still taking shape in computer and electronic laboratories, but there are some applications that provide an insight of what is coming in the next years. The development of virtual libraries will take place when libraries transform themselves into three dimensional electronic information centers. It will be possible when data storage, data representation and image processing technologies mature to cope with the great amounts of data graphically represented required by virtual information systems. In this paper, the upcoming of virtual information systems is discussed, defining the general concepts related to the topic and assessing the potential benefits for less developed countries.
Virtual reality (VR) is based on alternate reality, a man made illusion or replication of what happen or may happen in the real world. Therefore, alternate reality is not new. Movies and electronic machine games are two versions of the way that we see artificial reality. Books are another example of older technologies where humans create or narrate fictional reality. The difference between t hese means of alternate reality and virtual reality applications are that a book, for instance, is seen or read as an observer from outside while virtual reality allows the person to see things from inside the virtual information system (See table 1).
Immersion is the most important element of virtual reality and lets the user to see things from inside. Navigation is another characteristic that allows the user to move and therefore explore the cy berspace. The user can travel, walk, rotate, run and live through the virtual reality application. Another characteristic of virtual reality systems is that the inside observer can reach out and kn ock in the virtual world and get a response. He can manipulate, transform, erase and create new scenes or characters at his own will. In other words, VR systems are fully interactive and livable. Traditional media like books, journals or newspapers stimulate just one sense, that is vision. However virtual reality systems stimulates vision as well as hearing and touch. The user dips into thi s artificial world watching, listening and touching physical objects. In VR worlds anything can have a three dimensional (3-D) shape such as a thought, a concept or even a sound. In a summary, VR a llows the user to create an electronically manipulated reality (See table 1).
There are some technological developments that have to take place before virtual reality becomes a reliable technology. Liquid crystal display (LCD) screens need to be improved, the limited availabi lity of micro cathodic ray tubes (CRT) have also to be overcome as well as its cost (See table 3). Delay between user's movements and systems response needs to be solved. Systems need to be operate d in real time, and virtual reality developers have to master the ability to convey the virtual world, as well as to be able to generate images for complex scenes. These limitations will certainly b e overcome in the short run because the entertainment industry is highly interested in virtual reality, since it will revolutionize the way that we spent our free time.
Virtual reality is basically a fully interactive graphical information system, as such it has received attention in library literature [1,2,3]. The term virtual applied to libraries appears in the l iterature with different semantic connotations [4,10,11]. The most popular meaning is for those library services based on electronic information services transmitted via macro networks, such as Inte rnet. According to Rooks  the virtual library relies on electronic information systems, which uses "the most advanced high speed computing and telecommunication capabilities to the delivery and access of information resources." Some like Reynel  regards virtual libraries as those that may have fully digitized collections and electronic systems connected to other libraries of similar de velopment, so that the user can access information from any library as if it were at the reach of his computer terminal. However, VR scientist regard as virtual reality only those information produc ts where the user can immerse himself within the virtual world [5,7,9].
Normal media, like books, online databases and electronic video games, are seen or read from "outside" as an observer, but not within the product. In this sense, virtual libraries do not exist yet, since virtual information centers are not present. There are products for entertainment, education and scientific use. However, a center with a collection of such products or a complete virtual lib rary does not exist (See table 4). The future virtual library is likely to be a place with a fictional location where the user can penetrate, swim and walk through myriad of 3-D images with stimuli for most human senses. A library of this type may or may not resemblance a past, present or future passage of life, history or a natural phenomenon where the observer can interact with such fictiona l world.
The term virtual library is also used by some authors as synonym of digital library, but the second concept applies for those information resources that have been scanned using optical character reco gnition technologies. In other words, digital information is based on images of text, unlike electronic information that is originally generated as text. The first type uses more computer memory th an text based data, but it cannot be regarded as a virtual reality product. Digital or electronic products fail to provide immersion to the user, a basic function, as stated, required by VR informat ion systems. The term electronic library should be used to denote the new services provided by networked libraries, as it is used by Olsen  when he describes the Mann Library at Cornell Universit y which aims to be fully electronic, or by Senkevitch  description of Texas rural libraries' access to Internet information sources.
Virtual reality may potentially bring astonishing benefits to library users since information is presented in 3-D graphics. The basics skills of writing and reading will become probably secondary to use this new visual world. Books or virtual information systems will come alive with pictures, sound and smells of real life.
Libraries versus television. Virtual reality systems will empower traditional libraries, making possible for libraries to challenge television entertainment. It is said, that reading habits take mo re time to develop in children at present time due to the easiness of turning and watching television. VR information systems offer libraries the possibility of providing tools with full multimedia interacting power, besides the traditional printed and electronic services. The emerging information society will have a VR product that will meet the needs of audiovisual oriented users. Traditio nal television, except by interactive television, is a one way communication system, where the user is not able to interact. Even interactive television will still be based on watching in the short run, while VR lets the user to live within the information system and be part of it (See table 6)
Ideal information world. If virtual libraries resemblance traditional libraries the user will be able to open the main door of a library and navigate through shelves full of book spines, where he wil l choose the title and with the movement of a joystick, or even an eye movement may open a monograph. In this ideal information world, the user, since he or she may not be called reader anymore, wil l walk through a fictional life and jump from one scene to another and even navigate from one library to another. For example, novels will come alive playing the scores of music and set the characte rs in dancing action, if the topic is a musical, allowing the user to be part of the virtual living plot, interacting or transforming himself into the book's main character (See table 5).
This type of libraries are still to come. Whatever the form virtual libraries take, they will transform the concept of information. It will mean a copy of the real world or the VR expert view of a concept, story o phenomenon with such grotesque effects of futurist movies, cartoons or electronic games.
Virtual reality is a new technology that will affect developing countries as other new information technologies have. The rapid development of information technology is a major challenge because it grows faster than their economies. The advent of computers took years to arrive in LDC's libraries. It was until the mass production of personal computers when libraries acquired computer machines. VR is just the latest paradigm for libraries from developing economies. The technological gap may become now greater than ever before.
There is the feeling in LDCs that no matter how much a librarian tries to modernize information services, he will always face a time lag in using technology with regards to those from the developed n ations. Computers were the ultimate and definite goal to reach information modernity for most libraries in the South during the 80's. However, as soon as computers were at the reach for above the a verage library, networks become a must. Local area networks (LANs) are a reality in some libraries, but now wider area networks are the new standard. Plans are for creating open network systems and inter-connectivity via Internet is at a great pace in the industrialized world, that it seems unreachable for several LDCs.
Virtual reality might not be a concern in the short run in LDCs, because libraries, mainly from middle income countries, are working on electronic library applications, such is the creation of gopher s. However, it seems that they are, again, late in the world of Internet; the World Wide Web (WWW) is the new norm, since it requires even better telecommunications, solid networks and excellent wor kstations to handle greater graphical data. The higher income Latin American countries like Brazil, Mexico, Chile, Venezuela and Argentina have some library gophers, but fewer libraries have created Web home pages.
Mbambo's paper describes the networking limitations of Sub-Saharan african countries whose networks rely on switch packet technology to access remote Internet nodes. This means that library institut ions are left out of any Internet application because it becomes expensive, even just logging outside information resources.
The WWW is not even accessible to most libraries now in LDCs since it demands workstations with good technological capabilities. Personal computers (PC) stations require 8 megabytes of RAM memory an d they have to have a high definition monitor with fast microprocessors. PCs with these characteristics are in the top range price. LDC libraries that regard themselves to have "good computing equi pment" can aim to develop and use gophers, which need less trendy equipment.
The Gopher interface is more suitable at the moment, but the latest and more exciting Internet sources are available on Web browsers. This a major challenge to LDCs because some information sources on Internet are increasingly becoming the only place where to find them, such as logging to commercial online databases, bookdealers and to the cyber gossip of the networked world.
These recent electronic service developments place new challenges to developing countries but offer opportunities as well (See table 7). The opportunities are basically greater flexibility and conve nience for libraries users, since networks are integrating information systems into a single global network open to anyone who can access it.
Despite the overwhelming economic demands of electronic services, libraries from LDCs ought to pay attention to VR information systems, because it is a technology that may enable them to overcome som e social problems.
LDCs are characterized by illiteracy problems, and people who have access to schools often end up becoming functional illiterates since reading materials are not available. Training of the unemploye d is another burden because most teaching materials are in traditional printed media. Virtual reality offers a potential benefit to this population due to its graphic portray of the message. VR sys tems can be used to train illiterate people without need of writing and reading skills. VR products can overcome also language barriers, since language is not strictly required to replicated reality .
Testing and research of some scientific and industrial application will become cheaper. VR systems replicate real world problems, reducing the use of "real" materials. This will help LDCs to pursui t research endeavors with less economic investment (See table 8). However, there may be another world economic crisis or economic re-adjustment similar the one produced in the last decades due to th e reduction in size of most industrial goods, as well as the substitution of raw materials by synthetic products i.e. steel by plastic. This industrial changes brought economic problems to LDCs beca use their economy relies heavily in raw materials.
Virtual reality is a technology that will soon affect educational methods, training, information handling and the entertainment industry of the world. Virtual reality offers a great potential for ea sier and more attractive transmission of information because it is based on interactive graphics and images.
It overpasses present multimedia products, since virtual reality not only provides great images, but it gives the feeling to the user of being in the application. The user feels the system from insi de, something that is called immersion, plus the power of navigating and manipulation of the virtual world. Libraries with such characteristics do not exist yet.
The features of virtual reality systems will certainly affect the way that information is transferred from the author to the user. LDCs will benefit from this technology, if they can afford it. Vir tual reality systems may become the best tools for training, laboratory experimentation, and for almost any kind of information transmission without the limitation of language and printed media. A u ser from an LDC country will still require background knowledge to be able to grasp the virtual reality system content and the ability to manipulate such environment. The main barrier to the use of VR is the high cost that it has at the present time, but once its cost is reduced, it will be potential tool to speed out social development of countries from the South.
A problem that less development countries may also face is that highly developed countries will speed out the generation of knowledge consequently scientific and technological progress. This probabl e acceleration of knowledge in industrialized countries might be overcome by LDCs if they begin exploring and monitoring VR systems development. Otherwise the gap between the information-rich and th e information-poor will widen. The major challenge for LDCs is explore the use and effect of virtual reality in their own societies. Libraries need to monitor the role that virtual information syst ems may play in the way they transmit and diffuse knowledge.