📖 The World Wide Web is emerging as an important medium for the dissemination of information related to the wide range of topics. There are hundreds of millions of pages on the web today and this number is growing exponentially day by day. Looking for something valuable in this mammoth ocean of information is quite difficult. When searching the web, a user strives to find useful documents. Ordinary web search engines have been shown to have relatively low coverage, as well as other problems, that limit their ability to return useful documents. One solution is use of a multiple searching interface: a tool that sends user queries to multiple search engines and combines the results that are presented before the user. This increases the coverage and helps in realizing the power and benefits of different search engines.